Your Workbench disks are dead. The Amiga will retry a certain number of times before giving up and skipping the task, that's why it appears to have worked but hasn't.
You ought to have backups, but I'm guessing you don't. ;-) Whereabouts in the world are you? You may find someone here will be able to help you out.
Edit: Heh, the dude with the gigantic sig beat me to it ;-)
