sirnemo,
We (Corona Labs) didn’t write this plugin. You need to contact Tap-for-Tap for support on how to integrate their plugin and library into your Android project. I say that because we don’t know the specifics either. That said, I’m thinking you have to include more than just the TapForTap.jar file. You’ll likely have to include an additional JAR file that provides the Lua interface (ie: the Corona plugin interface) to the main TapForTap.jar file. Again, I’m speculating here, but that is typically how it works.
You can find their contact information and find their Corona Enterprise source code and instructions here…
http://docs.coronalabs.com/plugin/tapfortap/index.html#enterprise
If you feel that their instructions isn’t clear (and from the looks of things, they’re not), then let TapForTap know so that they can update their documentation.