Layout indistuctable

[M.A. Winterton]

I have a layout file done on CA a few versions back, can't open it, zip it, delete it, copy it, and it won't back up to DVD or CD burner. When I try to delete it, it comes up with "Cannot delete (file name) Data Error (cyclic redundancy check)" the plan file opens fine and the buildings built, so it doesn't worry me if I deleted it, I can always resend to a new layout if required. After a few goes I got the folder with plan in it to copy across out of my archives, so it's isolated and doen't keep mucking up my backups.

Anybody got any Ideas whats wrong with the file and how to I get rid of it?