Usually, when I see that logged, it's just a particular file that took too long. It's a bit odd that it's only showing C:\. Maybe it's trying to scan a non-existent file or something that was locked?
If i were you I would make sure that you don't have a local ODS task scheduled locally on the system. C:\Documents and Settings\All Users\Application Data\McAfee\Common Framework\Task. It will usually be a hexidecimal .INI file in this directory. I had some ODS scans running out of schedule and I couldn't figure out why until I looked locally on the system. If a user enabled the task locally the ePO server will not delete it. You have to do that manually.
These are just a guesses/suggestions - have you excluded SQL data and index file types in the OAS Server policy? Have you run chkdsk on the c: drive?