代码如下：
AVACL acl = new AVACL(mUser);
acl.setPublicReadAccess(true);
acl.setPublicWriteAccess(true);
AVRole role = new AVRole("common",acl);
role.getUsers().add(mUser);
LOG：
10-09 16:21:02.453: E/===AVOS Cloud===(17145): LogUtil$avlog->e->34: {"code":137,"error":"A unique field was given a value that is already taken."}
10-09 16:21:02.453: E/===AVOS Cloud===(17145): error:org.apache.http.client.HttpResponseException: Bad Request
10-09 16:21:03.072: E/===AVOS Cloud===(17145): LogUtil$avlog->e->34: {"code":1,"error":"Forbidden to find by class permissions."}
10-09 16:21:03.072: E/===AVOS Cloud===(17145): error:org.apache.http.client.HttpResponseException: Forbidden
10-09 16:21:04.140: E/===AVOS Cloud===(17145): LogUtil$avlog->e->34: {"code":101,"error":"Class or object doesn't exists."}
10-09 16:21:04.140: E/===AVOS Cloud===(17145): error:org.apache.http.client.HttpResponseException: Not Found
10-09 16:21:04.142: E/===AVOS Cloud===(17145): LogUtil$avlog->e->34: {"code":101,"error":"Class or object doesn't exists."}
10-09 16:21:04.142: E/===AVOS Cloud===(17145): error:org.apache.http.client.HttpResponseException: Not Found
请问一下，可能是什么原因导致的呢？
谢谢。