Had a bit of a cleanup with your code so try this:
<?php
ini_set ("display_errors", "1");
error_reporting(E_ALL);
$host = "";//edited out
$database = "";
$username = "";
$password = "";
$tbl_name = "users";
$link = mysqli_connect($host, $username, $password);
$conn = mysql_connect($host, $username, $password) or die("Could not connect: " . mysql_error());
mysql_select_db($database);
session_start();
if (isset($_SESSION['userid'])){
$userid=$_SESSION['userid'];
echo $userid;
}
//$currentUser = $_SESSION['myusername'];
//do some cleanup//
if (isset($_POST['submit'])){
$first = $_POST['first'];
$last = $_POST['last'];
$dob = $_POST['dob'];
$gender = $_POST['gender'];
$country = $_POST['country'];
$state = $_POST['state'];
$town = $_POST['town'];
$zip = $_POST['zip'];
$email = $_POST['email'];
//Clean them
$first = mysql_real_escape_string($first);
$last = mysql_real_escape_string($last);
$dob = mysql_real_escape_string($dob);
$gender = mysql_real_escape_string($gender);
$country = mysql_real_escape_string($country);
$state = mysql_real_escape_string($state);
$town = mysql_real_escape_string($town);
$zip = mysql_real_escape_string($zip);
$email = mysql_real_escape_string($email);
mysql_query ( "UPDATE users SET firstname='{$first}', lastname='{$last}', dob = '{$dob}', gender='{$gender}', country='{$country}', state='{$state}', town='{$town}', zip='{$zip}', email='{$email}' WHERE id={$userid}") or die(mysql_error());
}
if (isset($_SESSION['userid'])){
$userid=$_SESSION['userid'];
} else {
$getuserid=mysql_query ("SELECT id FROM users ORDER BY id DESC limit 1") or die(mysql_error());
while ($gtuserid = mysql_fetch_array($getuserid)) {
$theuserid=$gtuserid['id'];
$userid=$theuserid;
$_SESSION['userid']=$theuserid;
$userid=$_SESSION['userid'];
}//$getuserid
}// IF ELSE (isset($_SESSION['userid']))
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Connection</title>
<style type="text/css">
body {
font-family:Calibri;
font-size:1em;
}
.title {
font-size:1.6em;
font-weight:strong;
}
.links a{
font-size:1.2em;
text-decoration:none;
}
.links a:hover{
font-size:1.2em;
color:#0066FF;
text-decoration:none;
}
</style>
</head>
<body>
<p><span class="title">Add your personal information/span></p>
<form action="thebeast.php" method="post">
<p>
<input type="text" name="first" size="20" id="first" />
First name<br />
<input type="text" name="last" size="20" id="name" />
Last name<br />
<input name="dob" type="text" size="20" id="dob" ; } ?>
Date of Birth<br />
<input type="text" name="gender" size="20" id="gender" />
Gender <br />
<input type="text" name="country" size="20" id="country" />
Country<br />
<input type="text" name="state" size="20" id="state" />
State<br />
<input type="text" name="town" size="20" id="town" />
Town<br />
<input type="text" name="zip" size="20" id="zip" />
Zip Code<br />
<input type="text" name="email" size="40" id="email" />
Email<br />
<br />
<input type="submit" name="submit" value="Add your information" />
</form>
</body>
</html>
