[split] Bug in new form validation?

I can confirm a bug. I am getting two errors, when I am validating an e-mail address.

Code:

A PHP Error was encountered
Severity: Notice
Message: Use of undefined constant INTL_IDNA_VARIANT_UTS46 - assumed 'INTL_IDNA_VARIANT_UTS46'
Filename: libraries/Form_validation.php
Line Number: 1235

Code:

A PHP Error was encountered
Severity: Warning
Message: idn_to_ascii() expects parameter 3 to be integer, string given
Filename: libraries/Form_validation.php
Line Number: 1235

libraries/Form_validation.php

PHP Code:

/*Line 1230*/ public function valid_email($str)
/*Line 1231*/ {
/*Line 1232*/   if (function_exists('idn_to_ascii') && preg_match('#\A([^@]+)@(.+)\z#', $str, $matches))
/*Line 1233*/   {
/*Line 1234*/     $domain = is_php('5.4')
/*Line 1235*/       ? idn_to_ascii($matches[2], 0, INTL_IDNA_VARIANT_UTS46)
/*Line 1236*/       : idn_to_ascii($matches[2]);
/*Line 1237*/     $str = $matches[1].'@'.$domain;
/*Line 1238*/   }
/*Line 1239*/ 
/*Line 1240*/   return (bool) filter_var($str, FILTER_VALIDATE_EMAIL);
/*Line 1241*/ } 


An errors occuring only on one of my webhostings, so the problem could be in server configuration (I tried four different companies, localhost if also fine).

they were hapened to me