File: C:\Windows\SysWOW64\FsUsbExDisk.SYS - We got this error when a Windows 7 64-bit had updated the Samsung Kies software (used for the management of Samsung smartphones). Apparently this driver is not compatible with Windows 7 64 bit, however the software (Kies) worked fine after the update.
From a newsgroup post: “Here is the fix for Windows XP Pro x64 version:
1) Run regedit.
2) Search or manually find key:
3) Modify LowerFilers: Pfc.sys, deleting the entry Pfc.sys (it is not required for Windows XP 64-bit version).
4) Reboot the system. The events will no longer occur. Windows "rediscovers" the DVD drives after the reboot”. See the link to "pfc.sys error on WinXP Pro x64" for the original thread.
See the link to "Gear Software Forum Topic" for a discussion regarding this issue.