After the XE12 update, are any of you having trouble running the sample projects (compass, stopwatch, timer)?
When I try to run them, the programs just say "(program name) has stopped".
Have you updated your code to the latest versions? XE12 had a number of breaking API changes (such as renamed methods and classes).
You should make sure that the APKs that you've built are from the latest source, either in the add-on's samples directory or from Github, and the reinstall them.