Can't Access Site Admin

I can log in as an admin, but cannot get into Site Admin. This is the message I get.

"The administration session has expired, please re-authenticate to access the administration area."

I have already tried, clearing cache browser, clearing maintenance from http://~/gallery2/lib/support/index.php

I have also tried to log in with the default theme, but it did not work.

Gallery version (not just "2"): 2.3
PHP version (e.g. 5.1.6): 5.2.5
PHPInfo Link (see FAQ): http://www.cs.pitt.edu/~michal/gallery2/lib/support/index.php?phpinfo
Webserver (e.g. Apache 1.3.33): Apache/2.2.8
Operating system (e.g. Linux): Linux
Browser (e.g. Firefox 2.0): Any