خطای NullPointerException برای لایوت

سلام
علت این خطا چی میتونه باشه؟ هیچ رفرنسی به داخل سورس نداره و null توی لایوت داره رخ میده. کاملا هم غیر مشخص اتفاق میافته

  java.lang.NullPointerException
 at android.widget.FrameLayout.onLayout(FrameLayout.java:404)
 at android.view.View.layout(View.java:14471)
 at android.view.ViewGroup.layout(ViewGroup.java:4562)
 at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
 at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
 at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
 at android.view.View.layout(View.java:14471)
 at android.view.ViewGroup.layout(ViewGroup.java:4562)
 at android.widget.FrameLayout.onLayout(FrameLayout.java:452)
 at android.view.View.layout(View.java:14471)
 at android.view.ViewGroup.layout(ViewGroup.java:4562)
 at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1986)
 at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1740)
 at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1009)
 at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5508)
 at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
 at android.view.Choreographer.doCallbacks(Choreographer.java:562)
 at android.view.Choreographer.doFrame(Choreographer.java:532)
 at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
 at android.os.Handler.handleCallback(Handler.java:730)
 at android.os.Handler.dispatchMessage(Handler.java:92)
 at android.os.Looper.loop(Looper.java:213)
 at android.app.ActivityThread.main(ActivityThread.java:5225)
 at java.lang.reflect.Method.invokeNative(Native Method)
 at java.lang.reflect.Method.invoke(Method.java:525)
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
 at dalvik.system.NativeStart.main(Native Method)