[PHP] socket error

[sagar]

line10 -> if (($sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
                echo "socket() failed: reason: " . strerror($sock) . "\n";
                }

i'm getting an error saying
Fatal error: Call to undefined function: socket() in c:\program files\apache 
group\apache\htdocs\test\sock.php on line 10


can any one help

its urgent

/sagar