diff --git a/includes/form.inc b/includes/form.inc
index 3b2032e..50fef53 100644
--- a/includes/form.inc
+++ b/includes/form.inc
@@ -1440,7 +1440,7 @@ function _form_validate(&$elements, &$form_state, $form_id = NULL) {
       // length if it's a string, and the item count if it's an array.
       // An unchecked checkbox has a #value of integer 0, different than string
       // '0', which could be a valid value.
-      $is_empty_multiple = (!count($elements['#value']));
+      $is_empty_multiple = is_array($elements['#value']) && !count($elements['#value']);
       $is_empty_string = (is_string($elements['#value']) && drupal_strlen(trim($elements['#value'])) == 0);
       $is_empty_value = ($elements['#value'] === 0);
       if ($is_empty_multiple || $is_empty_string || $is_empty_value) {