Error on using a search value

Hi there, here is a weird one.

On this site using CB1.9, mtaq.org.au/index.php/component/comprofiler/userslist/Teacher%27s%20List/search

You can do any search using and value in the Primary Skill Taught (accredited): and it will return a result EXCEPT if you select any value that mentions 'guitar'

ie

Guitar - Classical
Guitar - Contemporary
Bass Guitar


Selecting one of these values gives an error -

Forbidden
You don't have permission to access /index.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

Any ideas why this would be happening?

JR

JR

Hello again, is there anybody that could give me even the faintest idea why this might be occurring?

Any help would be appreciated.

JR