Our site uses Drupal 5.7 and SMF 1.1.5.

I upgraded to the new SMFforum module for Drupal 5.x about two weeks ago. Now when someone tries to create a new account on our site, they get the following error message (modified, of course, to obscure file system details):

Fatal error: Call to undefined function smf_api_user_name_validate() in /home/examplesite/modules/smfforum/smfforum.module on line 1838

This is the block with line 1838:

// Validate the username:
  if (user_access('change own username') || user_access('administer users') 
|| !$user->uid) {
    if (!empty($edit['name']) && $edit['name'] != $user->name) {
      if (!smf_api_user_name_validate($edit['name']))
        form_set_error('name', t('The name %name is not valid in SMF.', 
array('%name' => $edit['name'])));

I have disabled the module for now to allow new accounts to be created, but obviously this is not the preferred solution. Can anyone help?