@wpJunkie, did you find any kind of resolution? I’m launching a site with a very similar setup, also using aMember. It’s been a challenge. I don’t remember if I’ve tested the ability to post to forums yet. I was wondering if you’re using the latest version of WPMU + BuddyPress (with bbPress built in) or if you were using one of the earlier versions of BuddyPress where bbPress was not built in with it.