Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.177
diff -u -p -r1.177 form.inc
--- includes/form.inc	31 Jan 2007 15:49:22 -0000	1.177
+++ includes/form.inc	10 Feb 2007 15:21:50 -0000
@@ -526,10 +526,7 @@ function _form_validate($elements, $form
   /* Validate the current input */
   if (!isset($elements['#validated']) || !$elements['#validated']) {
     if (isset($elements['#needs_validation'])) {
-      // An empty textfield returns '' so we use empty(). An empty checkbox
-      // and a textfield could return '0' and empty('0') returns TRUE so we
-      // need a special check for the '0' string.
-      if ($elements['#required'] && empty($elements['#value']) && $elements['#value'] !== '0') {
+      if ($elements['#required'] && strlen(trim($elements['#value'])) == 0) {
         form_error($elements, t('!name field is required.', array('!name' => $elements['#title'])));
       }