CMS v2.65 This Site says... There was an error sending the request! (403 Forbidden)

Hey Jayme, 

You could ask your host if they are able to disable mod_security for the CMSB directory only.  You could let them know it's a developer app much like phpMyAdmin and intentionally submits SQL and other code in the URL that triggers mod_security but is required to use the program.

mod_security lets you add custom rules, eg: anything with " SELECT " in the URL gets blocked.  So sometimes keen sysadmins add lots of extra rules and it starts creating a lot of false positives. 

Hope that helps!