I am running 2.9.2 and have asimilar problem:
‘An appropriate representation of the requested resource /wp-admin/users.php could not be found on this server.’
This happen when I try to view Users in the database beyond the initial page. It also is occuring when I Try to add a new user.
I thought it was a premissions problem, but changing to ‘755’ on user.php doesn’t cure it. Any Ideas?