Update your PHP to match:
<?php
session_start();
$dbcnx = @mysql_connect("xx", "xxx", "xx") or
die("ERROR: Unable to establish database connection");
$dbconn = @mysql_select_db("xxx") or
die( "Unable to select database");
if(isset($_POST['submit']))
{
$Forename = mysql_real_escape_string($_POST['Forename']);
$Surname = mysql_real_escape_string($_POST['Surname']);
$Password = mysql_real_escape_string($_POST['Password']);
$query = "SELECT * FROM `tblExplorerGroup` WHERE `Forename`='$Forename' AND `Surname`='$Surname' AND `Password`= '$Password'";
$result = mysql_query($query) or die("ERROR: " . mysql_error());
if(mysql_num_rows($result) > 0) # we found a match, so set $_SESSION flag:
{
$_SESSION['logged'] = TRUE;
// and assign a user_type SESSION value to the current user
$row = mysql_fetch_object($result);
$_SESSION['user_type'] = (strtolower($row->user_type) == 'leader') ? 'leader' : 'explorer';
if(isset($_SESSION['caller']))
{
header("Location: " . $_SESSION['caller']);
exit;
}
else # otherwise go to main page
{
header("Location: FrontPage.php");
exit;
}
}
else # invalid login, so create error message
{
$error = "<p id='error'>ERROR: Invalid user name and/or password.</p>";
}
}
?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>Please Login</title>
<link rel=stylesheet type="text/css" href="Style.css">
<style type="text/css">
<!--
fieldset {
width: 20em;
margin: 1em auto;
}
legend {
font-size: large;
font-weight: bold;
}
label {
float: left;
width: 6em;
}
fieldset p {
clear: both;
}
#error {
color: #c00;
font-weight: bold;
}
</style>
</head>
<body background="img/background.jpg" bottommargin="0" leftmargin="0" marginheight="0" marginwidth="0" rightmargin="0" topmargin="0">
<center><table width="765" height="100%" cellpadding="0" cellspacing="0" border="0" background="img/mainbackground.jpg"><tr valign="top"><td>
<table width="764" height="97" cellpadding="0" cellspacing="0" border="0">
<tr valign="top">
<td width="248"><!-- logo image --><img src="img/templogo.jpg" width="248" height="97" border="0" alt=""><!-- end logo image --></td>
<td width="100%" background="img/toplogobg.jpg"><img src="img/toplogobg.jpg" width="22" height="97" border="0" alt=""></td>
</tr>
</table>
<table width="764" height="42" cellpadding="0" cellspacing="0" border="0">
<tr valign="top">
<td width="169"><img src="img/left1.jpg" width="169" height="42" border="0" alt=""></td>
<td width="100%" background="img/left1bg.jpg"><img src="img/left1bg.jpg" width="20" height="42" border="0" alt=""></td>
</tr>
</table>
<table width="764" cellpadding="0" cellspacing="0" border="0">
<tr valign="top">
<td width="150">
</td>
<td width="10"> </td>
<td width="744">
<!-- add your content below -->
<BR>
<BR><BR><BR><BR>
<BR><BR><BR><BR><BR>
<center><form action='<?php echo $_SESSION['PHP_SELF'] ?>' method='post'>
<fieldset>
<legend>Log In</legend>
<p><label for="Forename">Forename:</label>
<input name="Forename" type="text" size="16" maxlength="16">
</p>
<p><label for="Surname">Surname:</label>
<input name="Surname" type="text" size="16" maxlength="16">
</p>
<p><label for="Password">Password:</label>
<input name="Password" type="password" size="16" maxlength="16">
</p>
<p><input type="submit" name="submit" value="Log In"></p>
<?php
if(!empty($error))
{
echo $error;
}
?>
</fieldset>
</form>
</center>
</td>
<td width="10"> </td>
</tr>
</table>
</td></tr></table></center>
</body>
</html>
And if you have not already done so add a user_type field to your tblExplorerGroup table. Then if you would like the user to be treated as a leader set the relative user's user_title value to leader
When you have done this you may retrieve the user type of any logged in user by accessing the user_type SESSION value:
// if the relative user is a leader redirect to 'index2.php'
if($_SESSION['user_type'] == 'leader')
{
header('Location: index2.php');
}
// otherwise (if the user is an explorer) redirect to 'index3.php'
else
{
header('Location: index3.php');
}