PGP and Windows XP SP3 hangs while docked

I have several dozen Dell Latitude E6400 and E6500 machines along with several Precision M6400s. We use the Dell E-Port Plus with all of these and they all work fine shutting down with Windows XP SP3 docked and undocked...UNTIL we install PGP version 9 or version 10. The laptop will then boot correctly and work fine; however, when you try to do a shut down or restart while docked, the system just hangs... I've had one go for as long as 72 hours... we finally just wind up holding the power button to shut it down. It seems that when the laptop is not docked, it still shuts down or restarts just fine. Would there be something on the E-Port plus that would cause PGP to hang? Thanks for any help!