try running the upgrade command from the command line before installing
the update, maybe SP2 didn't finish upgrading all the database schemas:
psconfig -cmd upgrade -inplace v2v -force -wait
(version to version upgrade)
or
psconfig -cmd upgrade -inplace b2b -force -wait
(build to build upgrade)
Then try running the update again.
--
regards,
Yury
http://www.xylos.com
http://ystex.net