Don't bother - that patch.data from 04/17/03 is the most recent. Beside, this isn't a patching issue.
So you're loading the game from MXM, right? Then IGR isn't an issue.
I'd tend to think a file may have been corrupted during the backup. Either it was written as corrupt, skipped, or written as a 0-byte file. Backup the game again. If you weren't using DVD2Xbox before, try using it this time. It's a better diagnostic tool than the others.