Why do I have this problem?
 

Every time I try to back up my system hard drive I keep getting these errors:

11:10:32 AM | Error | ditto: /System/Library/CoreServices/Certificate Assistant.app/Contents/Resources/3_CreateAndConfigure.bundle/Contents/Resources/no.lproj/KeyPairAttributes.nib/./keyedobjects.nib: Input/output error

I ended up deleting a few of these files, then trying again, but every time I get a new one.

I've already repaired any system files with the disk utility. Now what?
Help please.

Please send your log, with the "Send to shirt pocket" button, in to me at support.