I had a lot of trouble with 2.0 beta 7 and USB on WinXP.
Sometimes it wouldnt discover the empeg at all, other times it gave me that "unknown player" error. And sometimes in the middle of a synch it would drop the connection, and fail out.
I switched over to ethernet, and al is well.
Maybe related, maybe not.
My upgrade worked fine, and emplode 1.X also seemed to work fine. Granted I didnt use it all that long.

Zachary Volpicelli
Lost in Boston