What does this mean?

[maddento]

Warning: Invalid argument supplied for foreach() in /maddento/www/forum/global.php on line 54

It appears on my forum page when i type in the link

[Lynne]

Try disabling your modifications/plugins and see if you still have this problem.
Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php

define('DISABLE_HOOKS', true);