my code is as follows

<?php
include("config.php");

$ip=$_SERVER['REMOTE_ADDR']; 

if($_POST['id'])
{
    $id=$_POST['id'];
    $id = mysql_escape_String($id);

    $ip_sql=mysql_query("select ip_add from Voting_IP where mes_id_fk='$id' and ip_add='$ip'");
    $count=mysql_num_rows($ip_sql);

    if($count==0)
    {
        $sql = "update Messages set up=up+1  where mes_id='$id'";
        mysql_query($sql);

        $sql_in = "insert into Voting_IP (mes_id_fk,ip_add) values ('$id','$ip')";
        mysql_query($sql_in) or die(mysql_error());
        echo "<script>alert('Thanks for the vote');</script>";


    }
    else
    {
        echo "<script>alert('You have already voted');</script>";
    }

    $result=mysql_query("select up from Messages where mes_id='$id'");
    $row=mysql_fetch_array($result);
    $up_value=$row['up'];
    echo "<img src='button.png' width='110' height='90'>";
    echo $up_value;

}
?>

My problem is that the insert process doesnot take place at all. the script tags echos an alert box. even the img tag is echoed to the web page. but the insert process doesnot take place. the config file is fine.. note: this code works on my local machine which has php 5.3 but it doesnot work on the server which has php 5.2.. any advice..???