I have never seen this, but I'll offer this tip: Click View, then Preferences. When the Preferences box appears, select the Backup tab. Check what's in the Default Backup Filename Box. Make sure the drive and directory are valid.

0xFFFFFFFF is just another way of saying "-1." (If you don't know about binary storage, don't worry about why this is true.) A lot of functions return -1 to indicate an "unspecified failure." In the case of a backup, the first thing to verify would be that you're trying to write a backup file in a real location.