Suddenly cant make a post Urgent help needed pls

[Mariner1]

Ive just tried to make a post on my forum and i get this

Warning: require_once(includes/functions_ghsom.php) [function.require-once]: failed to open stream: No such file or directory in [path]/includes/functions_newpost.php(466) : eval()'d code on line 14

Fatal error: require_once() [function.require]: Failed opening required 'includes/functions_ghsom.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/networkc/public_html/includes/functions_newpost.php(466) : eval()'d code on line 14

Any ideas as earlier today everything was working ok.No one can make a post on my forum,