I am having problems with the Android New Horizons app (that I downloaded from Google Play) on my Google Nexus 7 16GB tablet.

1) While the table is flat on the desk the Heading value and display jumps from 356 to 31 degrees. The Calibrate button doesn't appear to help.
2) If I rotate the tablet while flat on the desk the Heading value and display does not change.
3) The Pitch and Roll values and display are stable but are half of the values that I would expect.
4) When I change Views the New Horizons app crashes "Unfortunately, com.paad.compass has stopped."

Thanks for your help.

P.S. I just purchased Professional Android 4 Application Development and like the book.