I have a problem in the same way, I think:

I have the Gold Edition of RTW, who install RTW plus BI without letting the choice...so everithing is at patch 1.5 , cause of the addon.

I create a copy of the repertory.
Install EB.
Crash.

Okay, now I manually wipe out BI, reinstall EB.
The game start ! Yes !!! Oh...no...the loading screen is the only thing I can have, the game doesn't load at all ( I've waited 25 minutes... )

I assume the core of the problem is that I have the Gold Edition, who's not a "virgin" RTW ?

Anyone can help ?