There is an issue with the Drupal Forms API in Drupal 5.x. It assumes there is one form on a page so it does not handle duplicate form IDs very well (read, at all!) - as such, if your forms are loaded in blocks or you just drupal_get_form() to load extra forms on a page in Drupal 5.x, you might well find yourself with several submit buttons all with an ID of id="edit-submit". Which sucks!