Blackberry will not activate on BES

Hi all,

We have a user that had a Blackberry Pearl device activated on our BES, and everything was working fine.  He had an issue with his device (the roller ball broke), so we wanted to move him to a new device.  We have done this plenty of times before with no issues...

However, this time, we simply cannot get the account to activate on any device!  We've tried activating *other* accounts on his device successfully, but his account will not activate.  We have deleted his account from the BES completely, re-created it, and still nothing...  We've tried activating his account on several different phones (a combination of Pearl's and Curve's). but still nothing.

RIM themselves have no idea what's wrong...

Anyone here happen to have any suggestions of what we can try...?  The error we get says that the server was not reachable (but when we activate a different account on the same domain, it works fine)...

By the way, the BES is talking to Exchange, if that makes any difference...  Typically, this is also one of the most sensitive users in our organization (CTO!), so the issue is urgent!

Thanks in advance for your help!

S.