在PHP页面上只显示了2002年每个套接字地址错误的一个用法

My website deployed on windows XP using WAMP. I see this error from last many days every thing were working fine. I don't know where is the problem. some buddy help

Warning: mysql_connect() [function.mysql-connect]: [2002] Only one usage of each socket address (protocol/network address/port) is normally permitted. (trying to connect via tcp://localhost:3306) in D:\wamp\www\ESP\ESP.php on line 7

where is the problem? my code or server side issue?

on line 7 this code is located

$con = mysql_connect($localhost,$root,$rootpass);//this is the line number 7
and it is unchanged from last many days. so why error now is showing?

and

$localhost = "localhost";