I have been having problems with PVMtpServicestart basically since the first day a got my Thunderbolt. The best I can find is that this process is related to Digital Rights Management and is constantly updating leading to the battery drain.
So far I have found that the Blockbuster app, USB Media syncing and restarting the phone all start this process. If I go in and force stop the process as soon as I restart my phone it seems to be fine, but if I sync the phone via USB even force stopping the process doesn't seem to work. I have not seen anything to indicate that HTC is aware of or looking in to the problem.