Why do I get zero sized reply???

[Pawe³]

Why after running the following script do I get zero sized reply??
It seems to hang when I access the $link_id (when comparing it, negating,
reading and so on) but it isn't an expected behaviour. Any clues??
Thanks,
Pawel Galecki
<?php
//db_connect.php
include "common_db.inc";
error_reporting(0);

$link_id = db_connect();
if(!$link_id) die(sql_error());
else echo "Successfully made a connection to $dbhost.<BR>";
?>

<?php
//common_db.inc
$dbhost = 'localhost';
$dbusername = 'phpuser';
$dbuserpassword = 'phppass';
$default_dbname = 'mysql';

$MYSQL_ERRNO = '';
$MYSQL_ERROR = '';

function db_connect() {
global $dbhost, $dbusername, $dbuserpassword, $default_dbname;
global $MYSQL_ERRNO, $MYSQL_ERROR;

$link_id = mysql_connect($dbhost, $dbusername, $dbuserpassword);
if(!$link_id) {
$MYSQL_ERRNO = 0;
$MYSQL_ERROR = "Connection failed to the host $dbhost.";
return 0;
}
else if(empty($dbname) && !mysql_select_db($default_dbname)) {
$MYSQL_ERRNO = mysql_errno();
$MYSQL_ERROR = mysql_error();
return 0;
}
else return $link_id;
}

function sql_error() {
global $MYSQL_ERRNO, $MYSQL_ERROR;

if(empty($MYSQL_ERROR)) {
$MYSQL_ERRNO = mysql_errno();
$MYSQL_ERROR = mysql_error();
}
return "$MYSQL_ERRNO: $MYSQL_ERROR";
}
?>