--- conditional_fields.old      2011-06-29 09:25:20.827412542 -0700
+++ conditional_fields.module   2011-06-29 09:25:00.198104896 -0700
@@ -995,6 +995,18 @@ function conditional_fields_check_empty(
   elseif (isset($field[0]['nid'])) {
     $value = $field[0]['nid'];
   }
+  // User reference
+  elseif (isset($field[0]['uid'])) {
+    $value = $field[0]['uid'];
+  }
+  // Role reference
+  elseif (isset($field[0]['rid'])) {
+    $value = $field[0]['rid'];
+  }
+  // Email field
+  elseif (isset($field[0]['email'])) {
+    $value = $field[0]['email'];
+  }

   if (!count($value) || (is_string($value) && drupal_strlen(trim($value)) == 0)) {
     return TRUE;