我在我们的项目中使用 Google API 进行 Google 身份验证，但是在制作发布签名的 APK 时，我们面临一些警告，因此我们无法生成签名的 APK。请指出实际问题在哪里。
[2013-06-01 10:32:01 - Proguard returned with error code 1. See console
[2013-06-01 10:32:01 - Note: there were 366 duplicate class definitions.
[2013-06-01 10:32:01 - Warning: library class android.net.http.AndroidHttpClient extends or implements program class org.apache.http.client.HttpClient
[2013-06-01 10:32:01 - Warning: com.google.android.gms.auth.GoogleAuthUtil: can't find referenced class com.google.android.gms.R
[2013-06-01 10:32:01 - Warning: com.google.android.gms.auth.GoogleAuthUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.auth.GoogleAuthUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.auth.GoogleAuthUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.auth.GoogleAuthUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can'tfind referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class com.google.android.gms.R$string
[2013-06-01 10:32:01 - Warning: com.google.android.gms.common.GooglePlayServicesUtil: can't find referenced class
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$RemoteRequest: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$RemoteRequest: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$RemoteRequest: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 -Warning: com.google.api.services.tasks.v1.Tasks$RemoteRequest: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$RemoteRequest: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$Tasklists$Delete: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$Tasklists$Delete: can't find referenced class com.google.api.client.http.HttpMethod
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$Tasklists$Get: can't find referenced class com.google.api.client.http.json.JsonHttpParser
[2013-06-01 10:32:01 - Warning: com.google.api.services.tasks.v1.Tasks$Tasklists$Get: can't find referenced field 'com.google.api.client.http.HttpHeaders headers' in class com.google.api.client.http.HttpResponse