I agree with whs in that norton can cause problems.
I have just looked around for some info regarding your problem
and specifically came arcross that problem as mentioned.
The following site may help you diagnose your problem: Here is a list of System Restore error messages:
Once at this site, select the error you are seeing from the
list numbered 1 - 13 (scroll to top of screen) and it will then
display possible causes including
programs which may interfere with the process.
Hope this helps