There was a major bug discovered in BES Express but has since been fixed in very recent releases. Sherry installed BES-X around May 15, and by May 25 it was fixed… The bug causes random problems with registering blackberry phones. This problem only occurs on networks where there is a zero in any of the octets. In this case, Shasta Mosquito, is a 10.0.0.0/24 network – so there was the problem. Updating the BES server to the latest release (or more specifically any release after 5.0.12) resolves this issue.