Have the same problem, same error code Module:8920, Error:215. Live Chat support had me run the removal tool and reinstall (I actually ran the removal tool, rebooted, reran the removal tool, rebooted then reinstalled). After the re-install, the problem was still there. All other updates work, and remain upon reboot. Had run a full scan before, even one in safe mode - no problem. Windows XP SP3 is completely upto date, qfecheck shows no MS patches missing. Also ran disk diags on off chance of a problem - no issue. No weird unsigned drivers too (sigverif).
The Live Chat interaction continued, and the rep. for some reason, without any explanation or permission, reset the winsock catalog, which caused the system to freeze upon shutdown. It took two hard reboots to get the system going again! When I tried to continue the Live chat, which returned after succesfully restarting, the rep didn't reply and finally terminated the connection. I received a phone call saying I'd get a call from another tech within an hour - didn't happen. I reopened the case, and am awaiting another call after receiving an email saying the problem would be escalated.
The LU log suggests this may be a failure in an attempt to update the Firefox Norton toobars, where it seems that those toolbars are in fact already properly installed. I suspect this may not have any critical bearing on the functionality of NIS2010, but is really a coding failure related to the live-update process. I'm surprised that nobody asked for a copy of the live-update log, which provides more specific information regarding return codes/failures in the live update process.
Frankly, I think this is a faillure in generating and using diagnostic information to pin-point actual problems, and then to do a proper repair. The idea that one has to do a clean removal, reinstall and then stab at things like clearing the winsock catalog just doesn't fly from the standpoint of proper SW debugging and repair processes.

There's a reason they get my money every year!