I think I had a similiar before and it turned out to be my theme I was using. Of course another time was my gl_access table was all messed up.
To make sure it isn't the gl_access issue, try going directly to the plugin admin, example...
Text Formatted Code
http://www.yoursite.com/admin/plugins/staticpages/index.php
If you are able to access it that way, then it may just be a theme issue, other wise you have some DB work ahead.
T.Marquez Jr. -
Webmaster -
www.indianapolisfilm.net - Geeklog 1.4.0sr5-1