Please help!!!

I've not changed anything since I last accessed my site, and when i went to it today I get the following error :

"XOOPS path check: Script is not inside XOOPS_ROOT_PATH and cannot run."

No page at all, nothing, just the error. I can't get to the admin page or anything. I've done a search and the only post I found was at Xoops but it doesn't relate to me because I've made no changes to my set up where as he had performed an update.

Has it been hacked? I notice that the error message is written on line 58 of mainfile.php in a section relating to protection against external scripts? I use Xoops 2.0.13.1

I have Protector installed and so thought I'd be protected against most attacks.

I am really desperate because the site is going to be showcased live in less than a week!! HELP!! Here is the URL - go and have a look...www.f3.org.uk

Ted