and I fixed the error
in the 2 modules there are some requires which looks like this :
PHP Code:
require_once(DIR . './includes/whatever.php');
couldn't work since it was looking in /var/www/forum./includes/whatever.php (as written in the fatal error)
so I made it look like this
PHP Code:
require_once(DIR . '/includes/whatever.php');
and it works fine now.
for your information there are 5 occurence of this bug in the comments module and 1 in the show comments module