as much as a pain in the but this make be back do a back up and not a sync with your device and reload the OS on the blackberry.
selective restore and hope it works from there.
if you want to back up from online and then bring it down from there in app world search for smrtguard app. it registers to your sim card. and works well for the same issue.
Current Device Bold 9900
Other Devices: to many to list before Signature restrictions