From everything I've read, once pfc.sys is used for the Samsung type DVD drive, its required for the drive to continue working. Any driver updates available on their site?
As far as GEAR, do a google just on the file name. There are many links with info on what devices to uninstall and what registry entries to modify depending on your error. This file is also related to your type of drive, but apparently it is fixable.
I don't even have a Samsung DVD drive (Unless they own Lite-On).
It's definitely put in place by ITunes because if I delete it ITunes yells at me saying its missing one of its beloved files. I found a registry edit for this for WinXP, but I don't know if it will be the same for Vista.
Thanks for your help