I would suggest that he disable the teatimer element of spybot and reboot as it can interfere with creation of startup entries and possibly in this case un-installation as it would be attempting to stop the deletion (uninstall) of an avast start-up entry.

Once he has rebooted he should then use the avast uninstall utility and reboot. Then if he absolutely must enable the teatimer again. Personally I think these start-up monitoring tools can be as much hassle as what they are trying to prevent (especially if the user doesn’t fully understand how they work), creation, modification or deletion of start-up entries.