App runs on API-7 emulator, but not the API-8 emulator

My app runs fine using the Android2.1 API-7 emulator, but it will not run on a DroidX 2.2.1 device, nor a Google_API-8 emulator. Has something changed from API-7 to API-8 that makes my program upward incompatible? This is my logcat error:

02-28 17:23:57.911: DEBUG/AndroidRuntime(15353): Shutting down VM 
02-28 17:23:57.911: WARN/dalvikvm(15353): threadid=1: thread exiting with uncaught exception (group=0x400208b0) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353): FATAL EXCEPTION: main 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353): java.lang.RuntimeException: Unable to instantiate application com.concbeam3.ConcBeam3: java.lang.ClassNotFoundException: com.concbeam3.ConcBeam3 in loader dalvik.system.PathClassLoader[/data/app/com.concbeam3-2.apk] 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:661) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4306) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.app.ActivityThread.access$3200(ActivityThread.java:129) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2145) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.os.Handler.dispatchMessage(Handler.java:99) 02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.os.Looper.loop(Looper.java:143) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at 开发者_JS百科android.app.ActivityThread.main(ActivityThread.java:4701) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at java.lang.reflect.Method.invokeNative(Native Method) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at java.lang.reflect.Method.invoke(Method.java:521) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at dalvik.system.NativeStart.main(Native Method) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353): Caused by: java.lang.ClassNotFoundException: com.concbeam3.ConcBeam3 in loader dalvik.system.PathClassLoader[/data/app/com.concbeam3-2.apk] 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at java.lang.ClassLoader.loadClass(ClassLoader.java:573) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at java.lang.ClassLoader.loadClass(ClassLoader.java:532) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.app.Instrumentation.newApplication(Instrumentation.java:942) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     at android.app.ActivityThread$PackageInfo.makeApplication(ActivityThread.java:656) 
02-28 17:23:57.969: ERROR/AndroidRuntime(15353):     ... 11 more 02-28 17:23:57.992: WARN/ActivityManager(17919):   Force finishing activity com.concbeam3/.Main

the manifest.xml reads:

<?xml version="1.0" encoding="UTF-8"?>
<manifest package="com.concbeam3"             xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName='"1.4"'>
<application android:label="@string/app_name" android:debuggable="true" android:icon="@drawable/ic_launcher_concrete" android:name="@string/app_name">
   <activity android:label="@string/app_name" android:name=".Main" android:configChanges="keyboardHidden|orientation" android:screenOrientation="portrait">
       <intent-filter>
           <action android:name="android.intent.action.MAIN"/>
           <category android:name="android.intent.category.LAUNCHER"/>
       </intent-filter>
   </activity>
      <activity android:name=".Help"/>
      <activity android:name=".About"/>
      <activity android:name=".Preferences"
                android:label="@string/app_name"/>
 </application>
<uses-sdk android:targetSdkVersion="8" android:minSdkVersion="8"/>
</manifest>

I started a new app with a different name and copied all of the files and code into the new app and it ruins on API-7 and API-8. I guess that there was a corruption in the file systems or with the signing. So... the solution was to start a fress app.