Error: MySQL Connection Failed: Can't create IP socket (10036)

The test scripts that produces the errors:

<?php
    mysql_connect("localhost:3306", "root", "");
?>

<?php
    mysql_connect("www.forum-verlag.com", "user", "password");
?>

On localhost: MySQL Server Version: 3.22.15-gamma
On remote host: MySQL Server Version 3.20.25

The error appears, although it is possible to connect to the server via myODBC or the mysql client. Even the Perl mysql modules work fine on mySQL.

So I suppose, the problem is PHP-related.