我正在尝试运行通用图像下载器示例，在导入和修复项目属性后，运行它时出现此错误。
UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already added: Lcom/nostra13/universalimageloader/cache/disc/BaseDiscCache;
at com.android.dx.dex.file.ClassDefsSection.add(ClassDefsSection.java:123)
at com.android.dx.dex.file.DexFile.add(DexFile.java:163)
at com.android.dx.command.dexer.Main.processClass(Main.java:486)
at com.android.dx.command.dexer.Main.processFileBytes(Main.java:455)
at com.android.dx.command.dexer.Main.access$400(Main.java:67)
at com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:394)
at com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:245)
at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:131)
at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:109)
at com.android.dx.command.dexer.Main.processOne(Main.java:418)
at com.android.dx.command.dexer.Main.processAllFiles(Main.java:329)
at com.android.dx.command.dexer.Main.run(Main.java:206)
at sun.reflect.GeneratedMethodAccessor138.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.android.ide.eclipse.adt.internal.build.DexWrapper.run(DexWrapper.java:180)
at com.android.ide.eclipse.adt.internal.build.BuildHelper.executeDx(BuildHelper.java:703)
at com.android.ide.eclipse.adt.internal.build.builders.PostCompilerBuilder.build(PostCompilerBuilder.java:577)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:728)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:321)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:396)
at org.eclipse.core.internal.resources.Project$1.run(Project.java:618)
at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
at org.eclipse.core.internal.resources.Project.internalBuild(Project.java:597)
at org.eclipse.core.internal.resources.Project.build(Project.java:124)
at com.android.ide.eclipse.adt.internal.project.ProjectHelper.doFullIncrementalDebugBuild(ProjectHelper.java:1000)
at com.android.ide.eclipse.adt.internal.launch.LaunchConfigDelegate.launch(LaunchConfigDelegate.java:147)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:855)
at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:704)
at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:1047)
at org.eclipse.debug.internal.ui.DebugUIPlugin$8.run(DebugUIPlugin.java:1251)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)
[2012-10-17 16:18:38 - com.nostra13.example.universalimageloader.HomeActivity] Dx 2 errors; aborting
[2012-10-17 16:18:38 - com.nostra13.example.universalimageloader.HomeActivity] Conversion to Dalvik format failed with error 1