I stand corrected
...Your backup is corrupted i.e system backup is different or was not written properly or some thing happened .
Copy the files except nandroid.md5 to another folder inside clockworkmod folder
Either you can also delete nandroid.md5 (keep it backed up in case ) and do the same
Go to adb shell and
md5sum *.* > nandroid.md5
You can do two things after this
A)Flash the ROM which was backed up by you .
Go to recovery
Factory reset it .(Just as a precaution)
Use advanced restore to restore data
Cache restore is pointless .system restore is not recommended since it might be corrupted.
In case of stock rom flash superuser zip for rooting
In case of locked bootloader flash recovery for recovery ...
B)Use complete restore .NOT Recommended but if you are feeling lucky go ahead ...