+When I try to uninstall Quicktime (iTunes is not on my system), the same error code pops up. What should I do?+
That one is often associated with file damage. (Especially if it is also mentioning a specific file and filepath on the PC.)
Try running a chkdsk over the drive whose drive letter is mentioned in the file path of the message. (If it's not mentioning a specific drive, run it on the Drive on which the QuickTime program files folder is stored.)
How to perform disk error checking in Windows XP
Does the chkdsk find/repair any damage? If so, does a QuickTime uninstall go through afterwards?