My Mac backs up my data using Apple's Time Machine backup software, and it backs up to a network fileserver thingbob. It's been doing this quite happily for the last couple of years, but a couple of months ago I would see the following message every week or two, and I would have to re-build my backup from scratch, which usually means leaving the laptop on and connected to the wireless for 18+ hours:
"Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you"
Well, somebody else has done all the hard work of finding a possible solution which doesn't involve nuking and re-building your backup, which you can find here:
Hopefully it'll help you fix your backup if you run into the same corruption problems I do :)