com.google.android.gsf package couldn't be found
Solution 1:
it seems to me like you're using the wrong emulator.
The default emulator uses a regular Android emulator that doesn't have any Google packages and can't run all sorts of things like maps, c2dm and all sorts of stuff like that.
what you want to do, is create a new emulator that can support the Google APIs.
then, when you run the project, choose the emulator that runs the target name Google APIs (Google Inc).
good luck.
Solution 2:
It's probably running on a device that doesn't support GCM, so your call to GCMRegistrar.checkDevice( this ); is throwing an exception. Check your logcat to be sure.
If you're testing it on an emulator, make sure you have the emulator set up to use Google APIs. When you create the emulator, the create new AVD window has a "Target" box. Select something in that box that says "Google APIs".