Index: contrib/field_usergroup.inc
===================================================================
--- contrib/field_usergroup.inc	(.../vendors/drupal_flexinode/4.6.0)	(revision 50558)
+++ contrib/field_usergroup.inc	(.../components/drupal_flexinode/4.6.0/src)	(revision 50558)
@@ -15,7 +15,10 @@
     } $where_sql = implode(' OR ', $where_roles);
   }
 
-  $result = db_query('SELECT DISTINCT(ur.uid), name FROM {users_roles} ur, {users} u WHERE (%s) AND ur.uid = u.uid ORDER BY name', $where_sql);
+  if(!empty($where_sql)) {
+      $where_sql = '(' . $where_sql . ') AND ';
+  }
+  $result = db_query('SELECT DISTINCT(ur.uid), name FROM {users_roles} ur, {users} u WHERE %s ur.uid = u.uid ORDER BY name', $where_sql);
   $selectable_users = array(); // stores 'em all.
   while ($user = db_fetch_object($result)) {
     $selectable_users[$user->uid] = $user->name;
@@ -75,4 +78,4 @@
 
 /** @} End of addtogroup themeable */
 
-?>
\ No newline at end of file
+?>