I need your help... I work on it until 3 days. My app is working with fragments. One of these fragments has to display a map from the Google Maps V2 api for Android.
Use MapView instead of MapFragment in your Fragment's layout. Remember to call MapView's lifecycle methods:
as described here.
Btw. you shouldn't be using MapFragment, only SupportMapFragment and support library.
Edit:
If you switch to support library, you can use code from comment #1 here: http://code.google.com/p/gmaps-api-issues/issues/detail?id=5064#c1