500 CGI error (session variables)

[mfaisalwarraich]

Hi Everybody,

I am submitting a form to the paypal and then returning to a url. return to the url is successful means the code is workin properly. but at the return url im having this 500 CGI error and it also not containing any values in the session variables. as im getting records and updating records if the return is successfull from paypal depending upon the session variables.

this is working fine at my server where i hosted it. but at other server its not working and having the problem which i mentioned above. the same code is not working on the other server. the troubleshooting has also done with the hosting company and they said there is problem with the code not with the CGI or any other thing. now im failed to understand that one code is working fine at one server and its not working (no values in the session) on the other. what should i do now? please help me so i can get rid of this problem.

if ($_REQUEST['action']=='success' && $_REQUEST['someid']<>''){
$order_id=$_REQUEST['someid'];
 
echo "<br />".$transection = "SELECT * FROM ".$GLOBALS['pre_tbl']."tran where id=".$id;
 
$transectionq = mysql_query($transection) or die(mysql_error());
$transrow=mysql_fetch_array($transectionq);
extract($transrow);
$tid=$ticket_id;
$qty=$no_tickets;
//echo "<br />".$userid    = $_SESSION['username']; 
echo "<br />".$user_id = "select * from ".$GLOBALS['pre_tbl']."user where email='$userid'";
$user_id_rs = mysql_query($user_id)or die(mysql_error());
$user_id_rows=mysql_fetch_array($user_id_rs);
$user_id = $user_id_rows['id'];
$first_name = $user_id_rows['first_name'];
$last_name = $user_id_rows['last_name'];
$user_name = $first_name." ".$last_name; 
echo "<br />".$querycheckshoworartist="SELECT e.type,e.event_id,s.eid,s.tid,s.orderid FROM ".$GLOBALS['pre_tbl']."seats s,".$GLOBALS['pre_tbl']."events e where s.tid=$tid and e.event_id=s.eid LIMIT 1";

this is not full code but a part from the code. in the above code the session has nothing if it is displayed. so im not able to execute SQL and get the result. this website is currently hosted at IXwebhosting where it has the problem. while its working fine at my server. please tell me how i can get rid of it. thanking you.