eregi_replace('ereg', 'preg', 'inside/User.php');

inside/User.php

@@ -337,7 +337,7 @@ class User {
 
   public function _validate() {
     $valid = true;
-    if (!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $this->email)) {
+    if (!preg_match("/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/i", $this->email)) {
       notify("Ugyldig format på epostadresse.");
       $valid = false;
     }