Zach,
Hence the testing required.
When you uninstall the agent I would reboot the computer, this would then allow the driver to be deleted.
Then have the agent reinstall.
This is why you may need to have the uninstall script run .. then reboot.. then reinstall, you may even need to reboot again.
Unfortunately this is not always an issue with the agent, but it is with Windows OS's. Windows is notorius for locking files and not allowing them to be removed until a service is stopped, which may require the reboot.
If you thing it's an agent issue.. I would definately open a SYMC case.
Hope this makes sense.
If this solves your questions please marked as solved.
Ronak