We have had the same problem when moving users, and apparently it's an ongoing thing with BlackBerries.
What you need to do (assuming there is no user data on the handheld to back up and restore) is:
1. Wipe the handheld by using the Security Menu ON THE HANDHELD.
2. Remove the user from the BlackBerry Manager.
3. Readd the user, and set an Activation password.
4. Activate the user FROM THE HANDHELD using Enterprise Activation and the password you set.
At no time during this process does the handheld need to be connected to your workstation.
This worked for us and reset the policy after much wailing and gnashing of teeth. If you have user data which needs to be backed up and restored, there is a much longer process (not tested by me) written by user DGMAN. Use the article link below to see the 20-step process:
http://www.blackberryforums.com/arch...hp/t-2988.html