We have a live site http://www.thebannerpeople.com if you try and log in or as an administrator if you visit edit user you get a 500 internal server error. Fortunately I am logged in from a previous session.

I have tried using garland and disabling all the custom modules, there is nothing much in the apache log nor the php error log. The drupal log is indicating the session has started for the user when i try to log in.

Any clues, we are desperate to find a resolution.