addview报错问题

code如下： mFill = (LinearLayout)findViewById(R.id.tianchong);

LinearLayout.LayoutParams parm = new LinearLayout.LayoutParams(mWidth,mListHeight*3/5);
LinearLayout L1 = new LinearLayout(getBaseContext());
L1.setLayoutParams(parm);
mFill.addView(L1);
xml：         <LinearLayout 
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:background="@color/grew"
     android:gravity="center"
     android:id="@+id/tianchong"
     android:orientation="vertical">
        
     </LinearLayout>       error log：05-10 06:06:28.534: ERROR/AndroidRuntime(775): ERROR: thread attach failed
05-10 06:06:28.614: DEBUG/dalvikvm(775): LinearAlloc 0x0 used 639500 of 5242880 (12%)
05-10 06:06:28.824: DEBUG/ddm-heap(781): Got feature list request
05-10 06:06:29.384: VERBOSE/HelloAndriod(781): VERBOSE
05-10 06:06:29.394: DEBUG/HelloAndriod(781): DEBUG
05-10 06:06:29.414: INFO/HelloAndriod(781): INFO
05-10 06:06:29.414: WARN/HelloAndriod(781): WARN
05-10 06:06:29.414: ERROR/HelloAndriod(781): ERROR
05-10 06:06:29.454: DEBUG/AndroidRuntime(781): Shutting down VM
05-10 06:06:29.454: WARN/dalvikvm(781): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
05-10 06:06:29.464: ERROR/AndroidRuntime(781): Uncaught handler: thread main exiting due to uncaught exception
05-10 06:06:29.474: ERROR/AndroidRuntime(781): java.lang.RuntimeException: Unable to start activity ComponentInfo{AReading_21.test/AReading_21.test.AReading_21}: java.lang.NullPointerException
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.os.Looper.loop(Looper.java:123)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.ActivityThread.main(ActivityThread.java:4363)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at java.lang.reflect.Method.invokeNative(Native Method)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at java.lang.reflect.Method.invoke(Method.java:521)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at dalvik.system.NativeStart.main(Native Method)
05-10 06:06:29.474: ERROR/AndroidRuntime(781): Caused by: java.lang.NullPointerException
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at AReading_21.test.AReading_21.onCreate(AReading_21.java:71)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
05-10 06:06:29.474: ERROR/AndroidRuntime(781):     ... 11 more
05-10 06:06:29.504: INFO/Process(52): Sending signal. PID: 781 SIG: 3
05-10 06:06:29.504: INFO/dalvikvm(781): threadid=7: reacting to signal 3
05-10 06:06:29.504: ERROR/dalvikvm(781): Unable to open stack trace file '/data/anr/traces.txt': Permission denied