All form builder functions' first parameters are $form_state

As mentioned at http://drupal.org/node/144132#comment-643920, if your menu item's page callback is set to 'drupal_get_form' and it's passed another function name as the argument, that other function needs to have $form_state listed as its first parameter, or you get all kinds of wacky results.

This might not be something Coder can actually check for, as I don't know that there's a universal way to tell whether a function is a form builder function or not.