Hi Conrad,
Welcome to Vista Forums!
The above procedure does seem applicable; however, I notice you have SP2. Has this been a problem since you installed SP1 and you just noticed or is this something new that occurred or did you just do a massive update installation including both service packs? Before you try this procedure, create a System Restore point AND backup the registry (just to be on the safe side in case this makes things worse - I'm a bit concerned that SP2 is installed and yet you still have this issue and I'm not completely certain how this will affect the system given all the subsequent updates). I'd give it a try and then test your system thoroughly (not just for that error message but to make sure everything else works as it should). Be prepared to restore if you encounter any problems.
If that doesn't work, try the following (which also has risks, so take the same System Restore and Registry Backup precautions first):
Boot into safe mode. First, open services and stop the Windows Management Instrumentation Service. Take ownership and give yourself full rights of the folder and the contents of the folder "C:\Windows\System32\wbem\Repository." Copy the entire Repository folder and make a backup folder called Repository-old in the wbem directory. Go to the Repository folder and delete the contents of the folder - but not the folder itself. Reboot. When you boot into Vista, you might notice a half dozen or so application errors...it's OK.
Reboot again, and Event ID 10 should be gone, along with the afore mentioned application errors.
If this doesn't work or causes more or different problems, then replace the Repository folder with the Repository-old folder you saved before you started and reboot and things should return to normal (though the Event 10 problem will not yet have been solved). If you can't get in to do that, then do the System Restore to get back to how it was before you started.
I hope this helps. If not, post back and we'll examine some other options after further research.
Good luck!