For me the "export signed application package" in eclipse always creates an APK but sometimes (right now it feels like more than 50%) when I copy the app on my phone I can't start the app because I immediately get a ClassNotFoundException. I checked it and sometimes classes are missing.
When I then close eclipse and start again and try to export again - it sometimes works.
That's very strange because,
- I normally don't get any "dalvik failed with error 1"
- when running the app directly on my phone I don't get any problems