2
Has your host done anything?
The error message is coming because of the safeguard introduced in 2.0.7 in mainfile.php that is protecting against inclusion of your mainfile by files on the same host, but outside the XOOPS root path.
If you think this is an unnecessary check, you can find this line in your mainfile.php:
define('XOOPS_CHECK_PATH', 0);
and change it to
define('XOOPS_CHECK_PATH', 1);