It's because of the two dots in the domain. It fails the regular expression.

I'll look into getting this fixed

If that can help...

function is_valid_email($email)
{
$atom = '[-a-z0-9!#$%&\'*+/=?^_`{|}~]'; // allowed characters for part before "at" character
$domain = '([a-z]([-a-z0-9]*[a-z0-9]+)?)'; // allowed characters for part after "at" character

$regex = '^' . $atom . '+' . // One or more atom characters.
'(\.' . $atom . '+)*'. // Followed by zero or more dot separated sets of one or more atom characters.
'@'. // Followed by an "at" character.
'(' . $domain . '{1,63}\.)+'. // Followed by one or max 63 domain characters (dot separated).
$domain . '{2,63}'. // Must be followed by one set consisting a period of two
'$'; // or max 63 domain characters.
return eregi($regex, $email);
}