If you've been having issues with corrupted Time Machine images either inside the Time Capsule or connected externally to your base station, the 7.4.1 firmware update (for all base stations from 2007 to today) plus the 10.5.6 update might help, according to TidBITS.
Apple says this update will fix problems that lead up to corruption issues, but TidBITS recommends you essentially start fresh just to make sure -- after using the Archive feature in Disk Utility to copy your previous Time Machine disk to an external drive. Don't have enough drives to do the data shuffle? You can always take your chances that you either don't have a corrupt Time Machine backup (which is pretty likely, honestly) or do a little soul/data-searching for anything you might want to preserve for posterity.
I don't use Time Machine as a sort of universal undo, but I understand some might. In either case: update your system and firmware as recommended by the manufacturer.