Are you working in Tier 1 or Tier 2?
Assuming Tier 1, did you start with the interpreter_android, interpreter_android_prebuilt or interpreter_android_prebuilt_lite directory to make your project?
The README.txt file in the interpreter_android directory doesn't tell you to change anything in the files. The one in the prebuilt ones does have instructions about what to change.
And you shouldn't change "com.thegamecreators.agkplayer" anywhere (at least not in the v10815 and up versions).
Quote: "bundle identifier?"
The bundle identifier is what makes each app unique on a device.
For instance, the basic AppGameKit Player (as delivered for the Android platform) is 'com.thegamecreators.agk_player'. It is also happens to be the package name, for the Android Player, referred to in the README.txt instructions.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master