我已经从 Xamrin 下载了软件包，当我安装 Xamarin 安装程序时，出现如下错误。我已经尝试过为 Android 安装 Xamarin Mono 中给出的说明，但得到了相同的结果。我已经尝试了 3 次。
日志：
[2013-04-23 03:53:28.841] [Info] Software item 'Xamarin.iOS for Visual Studio': not up to date
[2013-04-23 03:53:28.848] [Info] Component 'Xamarin.iOS for Visual Studio' v. 1.0.897 absent
[2013-04-23 03:53:28.856] [Info] Detection complete
[2013-04-23 03:53:36.597] [Debug] Waiting for initial task to complete.
[2013-04-23 03:53:36.606] [Debug] Initial task already completed.
[2013-04-23 03:53:36.617] [Debug] Detection completed.
[2013-04-23 03:53:42.250] [Info] User chose to update Android SDK at: <USER_HOME>\Android\android-sdk
[2013-04-23 03:53:45.272] [Info] 11 Android SDK components need to be downloaded.
[2013-04-23 03:53:45.281] [Debug] Enqueueing component: platform-tools ("platform tools")
[2013-04-23 03:53:45.289] [Debug] Enqueueing component: tools ("tools")
[2013-04-23 03:53:45.298] [Debug] Enqueueing component: android-7 ("Android SDK Platform 2.1_r3")
[2013-04-23 03:53:45.306] [Debug] Enqueueing component: android-8 ("Android SDK Platform 2.2_r3")
[2013-04-23 03:53:45.316] [Debug] Enqueueing component: android-10 ("Android SDK Platform 2.3.3._r2")
[2013-04-23 03:53:45.324] [Debug] Enqueueing component: android-12 ("Android SDK Platform 3.1, revision 3")
[2013-04-23 03:53:45.333] [Debug] Enqueueing component: android-14 ("Android SDK Platform 4.0")
[2013-04-23 03:53:45.340] [Debug] Enqueueing component: system-image-14 ("Android SDK Platform 4.0")
[2013-04-23 03:53:45.350] [Debug] Enqueueing component: android-15 ("Android SDK Platform 4.0.3")
[2013-04-23 03:53:45.361] [Debug] Enqueueing component: system-image-15 ("Android SDK Platform 4.0.3")
[2013-04-23 03:53:45.369] [Debug] Enqueueing component: NDK r8d ("Android NDK r8d (it may take a while)")
[2013-04-23 03:53:45.478] [Debug] Download service starting.
[2013-04-23 03:53:45.990] [Debug] Download size for 'http://dl.google.com/android/installer_r21-windows.exe': 77523031
[2013-04-23 03:53:45.998] [Debug] Download size for 'http://dl.google.com/android/repository/platform-tools_r16.0.2-windows.zip': 11948088
[2013-04-23 03:53:46.107] [Debug] Download size for 'http://dl.google.com/android/repository/tools_r21.1-windows.zip': 99246397
[2013-04-23 03:53:46.720] [Debug] Download size for 'http://dl.google.com/android/repository/android-2.1_r03-linux.zip': 70142829
[2013-04-23 03:53:46.728] [Debug] Download size for 'http://dl.google.com/android/repository/android-2.2_r03-linux.zip': 74652366
[2013-04-23 03:53:47.236] [Debug] Download size for 'http://dl.google.com/android/repository/android-2.3.3_r02-linux.zip': 85470907
[2013-04-23 03:53:47.345] [Debug] Download size for 'http://dl.google.com/android/repository/android-3.1_r03-linux.zip': 106472351
[2013-04-23 03:53:47.453] [Debug] Download size for 'http://dl.google.com/android/repository/android-14_r03.zip': 45919570
[2013-04-23 03:53:47.562] [Debug] Download size for 'http://dl.google.com/android/repository/sysimg_armv7a-14_r02.zip': 99621822
[2013-04-23 03:53:47.671] [Debug] Download size for 'http://dl.google.com/android/repository/android-15_r03.zip': 44414679
[2013-04-23 03:53:47.680] [Debug] Download size for 'http://dl.google.com/android/repository/sysimg_armv7a-15_r02.zip': 96227377
[2013-04-23 03:53:47.789] [Debug] Download size for 'http://dl.google.com/android/ndk/android-ndk-r8d-windows.zip': 327014028
[2013-04-23 03:53:48.599] [Info] Installation of software items starting.
[2013-04-23 03:53:48.610] [Debug] Checking software item 'Java JDK'
[2013-04-23 03:53:48.622] [Info] Software item 'Java JDK' does not need to be installed
[2013-04-23 03:53:48.631] [Debug] Checking software item 'Android SDK'
[2013-04-23 03:53:48.639] [Debug] Checking software item 'GTK#'
[2013-04-23 03:53:48.648] [Info] Software item 'GTK#' does not need to be installed
[2013-04-23 03:53:48.656] [Debug] Checking software item 'Xamarin Studio'
[2013-04-23 03:53:48.664] [Info] Software item 'Xamarin Studio' does not need to be installed
[2013-04-23 03:53:48.672] [Debug] Checking software item 'Xamarin.Android for Visual Studio and Xamarin Studio'
[2013-04-23 03:53:48.680] [Debug] Checking software item 'Xamarin.iOS for Visual Studio'
[2013-04-23 03:53:48.689] [Debug] Starting installation task.
[2013-04-23 03:53:48.697] [Info] Background installation worker called.
[2013-04-23 03:53:48.706] [Info] Processing software items
[2013-04-23 03:53:48.714] [Info] Skipping installation of software item 'Java JDK'
[2013-04-23 03:53:48.721] [Info] Installing software item 'Android SDK'
[2013-04-23 03:53:48.729] [Info] Android SDK is waiting for download to finish.
[2013-04-23 03:53:51.648] [Debug] Download size for 'http://download.xamarin.com/MonoforAndroid/Windows/mono-android-4.6.04000.msi': 163536039
[2013-04-23 03:53:51.957] [Debug] Download size for 'http://download.xamarin.com/MonoTouchforVisualStudio/Windows/mtvs-1.0.897.0.msi': 44552752
[2013-04-23 03:53:51.965] [Info] Downloading from 'http://dl.google.com/android/installer_r21-windows.exe'.
[2013-04-23 03:53:51.973] [Debug] Setting download timeout for 'http://dl.google.com/android/installer_r21-windows.exe' to 60s
[2013-04-23 04:17:43.137] [Info] Downloading from 'http://dl.google.com/android/repository/platform-tools_r16.0.2-windows.zip'.
[2013-04-23 04:17:43.148] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/platform-tools_r16.0.2-windows.zip' to 60s
[2013-04-23 04:17:43.458] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\platform-tools_r16.0.2-windows.zip is a valid ZIP archive
[2013-04-23 04:17:43.467] [Debug] URL http://dl.google.com/android/repository/platform-tools_r16.0.2-windows.zip already fully downloaded.
[2013-04-23 04:17:43.475] [Info] Downloading from 'http://dl.google.com/android/repository/tools_r21.1-windows.zip'.
[2013-04-23 04:17:43.483] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/tools_r21.1-windows.zip' to 60s
[2013-04-23 04:17:43.693] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\tools_r21.1-windows.zip is a valid ZIP archive
[2013-04-23 04:17:43.705] [Debug] URL http://dl.google.com/android/repository/tools_r21.1-windows.zip already fully downloaded.
[2013-04-23 04:17:43.714] [Info] Downloading from 'http://dl.google.com/android/repository/android-2.1_r03-linux.zip'.
[2013-04-23 04:17:43.725] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/android-2.1_r03-linux.zip' to 60s
[2013-04-23 04:17:43.936] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\android-2.1_r03-linux.zip is a valid ZIP archive
[2013-04-23 04:17:43.945] [Debug] URL http://dl.google.com/android/repository/android-2.1_r03-linux.zip already fully downloaded.
[2013-04-23 04:17:43.953] [Info] Downloading from 'http://dl.google.com/android/repository/android-2.2_r03-linux.zip'.
[2013-04-23 04:17:43.961] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/android-2.2_r03-linux.zip' to 60s
[2013-04-23 04:17:44.271] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\android-2.2_r03-linux.zip is a valid ZIP archive
[2013-04-23 04:17:44.281] [Debug] URL http://dl.google.com/android/repository/android-2.2_r03-linux.zip already fully downloaded.
[2013-04-23 04:17:44.293] [Info] Downloading from 'http://dl.google.com/android/repository/android-2.3.3_r02-linux.zip'.
[2013-04-23 04:17:44.302] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/android-2.3.3_r02-linux.zip' to 60s
[2013-04-23 04:17:44.715] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\android-2.3.3_r02-linux.zip is a valid ZIP archive
[2013-04-23 04:17:44.724] [Debug] URL http://dl.google.com/android/repository/android-2.3.3_r02-linux.zip already fully downloaded.
[2013-04-23 04:17:44.733] [Info] Downloading from 'http://dl.google.com/android/repository/android-3.1_r03-linux.zip'.
[2013-04-23 04:17:44.741] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/android-3.1_r03-linux.zip' to 60s
[2013-04-23 04:17:44.952] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\android-3.1_r03-linux.zip is a valid ZIP archive
[2013-04-23 04:17:44.960] [Debug] URL http://dl.google.com/android/repository/android-3.1_r03-linux.zip already fully downloaded.
[2013-04-23 04:17:44.971] [Info] Downloading from 'http://dl.google.com/android/repository/android-14_r03.zip'.
[2013-04-23 04:17:44.980] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/android-14_r03.zip' to 60s
[2013-04-23 04:17:46.500] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\android-14_r03.zip is a valid ZIP archive
[2013-04-23 04:17:46.508] [Debug] URL http://dl.google.com/android/repository/android-14_r03.zip already fully downloaded.
[2013-04-23 04:17:46.517] [Info] Downloading from 'http://dl.google.com/android/repository/sysimg_armv7a-14_r02.zip'.
[2013-04-23 04:17:46.525] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/sysimg_armv7a-14_r02.zip' to 60s
[2013-04-23 04:17:46.534] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\sysimg_armv7a-14_r02.zip is a valid ZIP archive
[2013-04-23 04:17:46.642] [Debug] URL http://dl.google.com/android/repository/sysimg_armv7a-14_r02.zip already fully downloaded.
[2013-04-23 04:17:46.652] [Info] Downloading from 'http://dl.google.com/android/repository/android-15_r03.zip'.
[2013-04-23 04:17:46.661] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/android-15_r03.zip' to 60s
[2013-04-23 04:17:46.973] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\android-15_r03.zip is a valid ZIP archive
[2013-04-23 04:17:46.982] [Debug] URL http://dl.google.com/android/repository/android-15_r03.zip already fully downloaded.
[2013-04-23 04:17:46.990] [Info] Downloading from 'http://dl.google.com/android/repository/sysimg_armv7a-15_r02.zip'.
[2013-04-23 04:17:46.999] [Debug] Setting download timeout for 'http://dl.google.com/android/repository/sysimg_armv7a-15_r02.zip' to 60s
[2013-04-23 04:17:47.108] [Debug] File <USER_HOME>\Temp\Xamarin\downloads\sysimg_armv7a-15_r02.zip is a valid ZIP archive
[2013-04-23 04:17:47.117] [Debug] URL http://dl.google.com/android/repository/sysimg_armv7a-15_r02.zip already fully downloaded.
[2013-04-23 04:17:47.125] [Info] Downloading from 'http://dl.google.com/android/ndk/android-ndk-r8d-windows.zip'.
[2013-04-23 04:17:47.134] [Debug] Setting download timeout for 'http://dl.google.com/android/ndk/android-ndk-r8d-windows.zip' to 60s
[2013-04-23 04:53:23.445] [Exception] Failed to retrieve response for URL 'http://dl.google.com/android/ndk/android-ndk-r8d-windows.zip'
[2013-04-23 04:53:23.445] [Exception] System.Net.WebException: The operation has timed out.
[2013-04-23 04:53:23.445] [Exception] at System.Net.ConnectStream.Read(Byte[] buffer, Int32 offset, Int32 size)
[2013-04-23 04:53:23.445] [Exception] at Xamarin.Web.Installer.DownloadService.DoDownload(Int64 totalBytes, Stream responseStream, Stream outputStream, Object state)
[2013-04-23 04:53:23.445] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(HttpWebResponse response, String url, Action`4 doDownload, Boolean noCache, Object state)
[2013-04-23 04:53:23.445] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(String url, Action`4 doDownload, Func`3 webExceptionHandler, Boolean noCache, Object state, Int32 timeout)
[2013-04-23 04:53:23.960] [Exception] Zip verification exception
[2013-04-23 04:53:23.960] [Exception] Ionic.Zip.BadReadException: Could not read block - no data! (position 0x0387D7D6)
[2013-04-23 04:53:23.960] [Exception] at Ionic.Zip.SharedUtilities._ReadFourBytes(Stream s, String message)
[2013-04-23 04:53:23.960] [Exception] at Ionic.Zip.ZipEntry.HandleUnexpectedDataDescriptor(ZipEntry entry)
[2013-04-23 04:53:23.960] [Exception] at Ionic.Zip.ZipEntry.ReadEntry(ZipContainer zc, Boolean first)
[2013-04-23 04:53:23.960] [Exception] at Ionic.Zip.ZipInputStream.GetNextEntry()
[2013-04-23 04:53:23.960] [Exception] at Xamarin.Web.Installer.Utilities.IsValidFile(String path)
[2013-04-23 04:53:24.068] [Exception] Error downloading URL 'http://dl.google.com/android/ndk/android-ndk-r8d-windows.zip' requested by 'Android SDK, web exception was thrown. Connection timed out
[2013-04-23 04:53:24.068] [Exception] System.Net.WebException: The operation has timed out.
[2013-04-23 04:53:24.068] [Exception] at System.Net.ConnectStream.Read(Byte[] buffer, Int32 offset, Int32 size)
[2013-04-23 04:53:24.068] [Exception] at Xamarin.Web.Installer.DownloadService.DoDownload(Int64 totalBytes, Stream responseStream, Stream outputStream, Object state)
[2013-04-23 04:53:24.068] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(HttpWebResponse response, String url, Action`4 doDownload, Boolean noCache, Object state)
[2013-04-23 04:53:24.068] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(String url, Action`4 doDownload, Func`3 webExceptionHandler, Boolean noCache, Object state, Int32 timeout)
[2013-04-23 04:53:24.068] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(String url, Action`4 doDownload, Boolean noCache, Object state, Int32 timeout)
[2013-04-23 04:53:24.068] [Exception] at Xamarin.Web.Installer.DownloadService.DownloadItem(DownloadServiceWorkItem item, Boolean firstDownload)
[2013-04-23 04:53:24.178] [Info] Downloading from 'http://download.xamarin.com/MonoforAndroid/Windows/mono-android-4.6.04000.msi'.
[2013-04-23 04:53:24.187] [Debug] Setting download timeout for 'http://download.xamarin.com/MonoforAndroid/Windows/mono-android-4.6.04000.msi' to 60s
[2013-04-23 04:53:24.196] [Exception] Android SDK: download failed with exception.
[2013-04-23 04:53:24.197] [Exception] System.Net.WebException: The operation has timed out.
[2013-04-23 04:53:24.197] [Exception] at System.Net.ConnectStream.Read(Byte[] buffer, Int32 offset, Int32 size)
[2013-04-23 04:53:24.197] [Exception] at Xamarin.Web.Installer.DownloadService.DoDownload(Int64 totalBytes, Stream responseStream, Stream outputStream, Object state)
[2013-04-23 04:53:24.197] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(HttpWebResponse response, String url, Action`4 doDownload, Boolean noCache, Object state)
[2013-04-23 04:53:24.197] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(String url, Action`4 doDownload, Func`3 webExceptionHandler, Boolean noCache, Object state, Int32 timeout)
[2013-04-23 04:53:24.197] [Exception] at Xamarin.Web.Installer.Utilities.DownloadUrl(String url, Action`4 doDownload, Boolean noCache, Object state, Int32 timeout)
[2013-04-23 04:53:24.197] [Exception] at Xamarin.Web.Installer.DownloadService.DownloadItem(DownloadServiceWorkItem item, Boolean firstDownload)
[2013-04-23 04:53:24.205] [Info] Status: failed.
[2013-04-23 04:53:24.214] [Exception] Installation of software item 'Android SDK' failed with exception.
[2013-04-23 04:53:24.214] [Exception] Xamarin.Web.Installer.InstallException: Download failed. ---> System.Net.WebException: The operation has timed out.