Editing clinic press theme settings

I get the following error page when I am trying to change general settings of the clinicpress theme from the dashboard

"The requested URL /wp-admin/admin.php was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."

What is causing this error and how can I resolve it.

The theme is installed on WordPress 3.5.1

Thanks