Fatal error - please help

After 3 months of the forum working well, all of a sudden whenever a user tries to enter the forum, they get the following error message:

Parse error: syntax error, unexpected ';' in /mounted-storage/home86b/jx7j/www/gallery/phpdatabase.php(526) : runtime-created function on line 1

Fatal error: require() [function.require]: Failed opening required 'lang/' (include_path='.:/usr/local/lib/php/') in /mounted-storage/home86b/jx7j/www/gallery/language.php on line 7

Any idea why?

Thanks.