IAX Settings Page Error

I’m using the newest distro (1.811.210.57-1)and having a problem enabling the g729 codec on the IAX settings page. Every time I check the box I get:

Not Found The requested URL /admin/a was not found on this server. Apache/2.2.3 (CentOS) Server at Port 80

I get this in both firefox and ie9. Is this a bug or just on my install?