How about an image? Or a link to your forum? Do you have an modifications that may be doing this? Try turning them off and see:
Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php
PHP Code:
define('DISABLE_HOOKS', true);
Don't forget that for vbseo, disabling the modification means to also get rid of anything extra you added to your htaccess file.