PHP $_Session variable not recognised

I'm trying to differentiate between an admin user and a client with the session variable. Depending on their user type, they will be shown different content of the page. In order to do that, I wanted to check the user's type in the database depending on the $_SESSION after login. It's not an ideal solution but the simplest I can think of, yet I still can't get this to work. Database table holding user details is called LS_Users and the field storing user type (values: either "A" for admin or "C" for client) is called userType.

The problem I'm having is that the user type is not being picked up properly.

The code below doesn't read the user type.

$usertype = isset($_POST['userType']) ? $_POST['userType'] : $_SESSION['userType'];
$usertype=$_POST['user_type'];
 $thisuserSQL="select * from LS_Users where  userType = '".$usertype."'";
 $exethisuserSQL=mysql_query($thisuserSQL) or die (mysql_error());
 $userArray=mysql_fetch_array($exethisuserSQL);
 if ($userArray['userType']!=$usertype)
 {
  echo "Usertype: ".$_SESSION['userType'];
 }
 else
 {
  echo "Usertype: empty";
 }

And the code below returns the first value from the database instead of matching it to the actual user that logged in.
if ($_SESSION['c_userid'])
{
 echo "Name: ".$_SESSION['c_fname'].", Id: ".$_SESSION['c_userid'], "Usertype: ".$_SESSION['userType'];
 echo "<hr>";
 $usertype = $_REQUEST['userType'];
 $currentuserSQL="select * from LS_Users";
// where userType =" '$usertype';
 $execurrentuserSQL=mysql_query($currentuserSQL) or die (mysql_error());
 $userArray=mysql_fetch_array($execurrentuserSQL);
$_SESSION['c_userid']=$userArray['user_id'];
 $_SESSION['userType']=$userArray['userType'];

 echo "<p>Hello, ".$_SESSION['c_fname']."! ";

 if ($_SESSION['userType']== "C")
  {
  echo "<p>Client";
  }
 elseif ($_SESSION['userType']== "A")
  {
  echo "<p>Admin";
  }
 else
 {
  echo "<p>Empty";
  }
}
else
{
 echo "Please log in.";
}

Many thanks for your help

Did you include the magical session_start(); function into your code?

Put it in the very beginning of every file which uses sessions:

<?php
  session_start();
  ...

If the problem only happens for the userType, I would like to verify that your php configuration does not have the register_globals activated. If it does, it might be the source of your problems. Otherwise, please answer the following questions:

Are you sure the other session variables are working?
Are you sure the initialization of the $_SESSION['userType'] is working?
Can you write it after having initialized it?