java Android:无法实例化活动组件信息

Question

我得到以下错误，我不知道该怎么办。我清除了我的项目100次，从构建路径中删除了所有jar，删除了bin和gen。。。。。但对我来说什么都不管用
请在下面查找错误代码：

09-03 19:43:17.326: E/Trace(800): error opening trace file: No such file or directory (2)
09-03 19:43:17.546: D/AndroidRuntime(800): Shutting down VM
09-03 19:43:17.597: W/dalvikvm(800): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
09-03 19:43:17.629: E/AndroidRuntime(800): FATAL EXCEPTION: main
09-03 19:43:17.629: E/AndroidRuntime(800): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.firsttravel/com.example.firsttravel.MainActivity}: 
java.lang.ClassNotFoundException: Didn't find class "com.example.firsttravel.MainActivity" on path: /data/app/com.example.firsttravel-2.apk
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.ActivityThread.access$600(ActivityThread.java:141)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.os.Handler.dispatchMessage(Handler.java:99)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.os.Looper.loop(Looper.java:137)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.ActivityThread.main(ActivityThread.java:5041)
09-03 19:43:17.629: E/AndroidRuntime(800):  at java.lang.reflect.Method.invokeNative(Native Method)
09-03 19:43:17.629: E/AndroidRuntime(800):  at java.lang.reflect.Method.invoke(Method.java:511)
09-03 19:43:17.629: E/AndroidRuntime(800):  at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
09-03 19:43:17.629: E/AndroidRuntime(800):  at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:560)
09-03 19:43:17.629: E/AndroidRuntime(800):  at dalvik.system.NativeStart.main(Native Method)
09-03 19:43:17.629: E/AndroidRuntime(800): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.firsttravel.MainActivity" on path: /data/app/com.example.firsttravel-2.apk
09-03 19:43:17.629: E/AndroidRuntime(800):  at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
09-03 19:43:17.629: E/AndroidRuntime(800):  at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
09-03 19:43:17.629: E/AndroidRuntime(800):  at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.Instrumentation.newActivity(Instrumentation.java:1054)
09-03 19:43:17.629: E/AndroidRuntime(800):  at 安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
09-03 19:43:17.629: E/AndroidRuntime(800):  ... 11 more
09-03 19:43:54.849: I/Process(800): Sending signal. PID: 800 SIG: 9`

你们知道怎么回事吗

多谢各位