Good suggestions so far - I just joined this community, but it seems to be a good one!
I'm using an 8100 and running into the same issues. However, I'm not on a BES, so I can't tweak that.
I did hear that I'm supposed to use the "default windows bluetooth driver", so I went to windows update and downloaded the version they suggested for my thinkpad. still - no luck...I can connect in xp, but I can't via the blackberry manager.
Any other ideas?