Do you have a problem with some Drupal admin pages with a large number of input fields not saving? Does the page just returns back with no message confirming that changes have been saved?
Well, this happened recently on a site that we were troubleshooting for a client.
The symptoms were: trying to save has lots of input fields, a) comes back with no message about saving changes, and b) the values changed were not saved.
The site had 210 enabled modules, 14 user roles defined, and 84 content types, with 76 content fields!