(I am at work so I am quoting myself from memory from last night...)
It looks like 2.5 may have changed the way that user levels are addressed in the $userdata array. Because of this, the administration page required a quick and dirty hack to make it go.
I am new to WordPress but old to PHP, so I was able to dump the administrator boolean value to the existing $bcm_user_level variable and make it go.
Other than this hang-up, it appears to work just as flawlessly as it did with 2.3. This is one of my favorite plug-ins for WordPress so far, and highly recommend it to everyone.