Otra vez la pagina en blanco mas resumido

Vale e estado leyendo y la pagina en blanco es un error que se oculta en CMS o wordpress yo tengo cms vale ahora no se como sacar el error e intentado muxas cosas y nada aqui os dejo el register.ctp donde se supone que esta el registro:

<div class="users register-page">
<h1 class="page-title">Register</h1>

<div class="col1">
<div class="form-block">
<div class="content">
<fieldset>
<legend></legend>
<span style="color:red">
<?php
$hostdb1 = "rdbms.strato.de";
$userdb1 = "oculto";
$pwdb1 = "oculta";
$dbdb1 = "oculto";
$domain = 'http://premierbid.es' /*without http or www or backend slash*/
/*DO NOT EDIT BELOW THIS LINE*/
$con = mysql_connect("$hostdb1","$userdb1","$pwdb1");
$errormessage = '';
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("$dbdb1", $con);
if ((isset($_GET['key']))&&(isset($_GET['username']))){
$thename = $_GET['username'];
$thekey = $_GET['key'];
$errormessage = 'Invalid key';
$sql = "SELECT `username` FROM users WHERE (username='$thename') AND (`key`='$thekey')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
else{
$errormessage = 'User is already active !';
$sql = "SELECT `username` FROM users WHERE (username='$thename') AND (`active`='0')";
$check = mysql_num_rows(mysql_query($sql,$con));
if ($check==1) {
$sql = "UPDATE `users` SET active='1' WHERE (username='$thename') AND (`key`='$thekey')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
else{
$errormessage = 'Activation successfull !';
}
}
echo $errormessage; }
}
elseif (isset($_POST['submit'])) {
if ((strlen($_POST['username'])<6)||(strlen($_POST['pw'])<6)||(strlen($_POST['pw2'])<6)||(strlen($_POST['email'])<6)) {
$errormessage= 'Please complete all mandatory(*) fields with the asked length';
}
elseif(($_POST['pw']) !== ($_POST['pw2'])) {
$errormessage = 'Passwords do not match';
}

else {
if (isset($_POST['email'])) {if(eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $_POST['email'])) {
$username = $_POST['username'];
$check = mysql_num_rows(mysql_query("SELECT `username` FROM users WHERE username='$username'"));
if($check=="1")
{ $ok = false;
$errormessage = '
Sorry, the username <i><b>'.$username.'</b></i> is already taken.<br />Please choose another one.<br /><br />';
}

$email = $_POST['email'];
$check = mysql_num_rows(mysql_query("SELECT `email` FROM users WHERE `email`='$email'"));
if($check=="1")
{ $ok = false;
$errormessage = '
Sorry, the email <i><b>'.$email.'</b></i> is already taken.<br />Please choose another one.<br /><br />';
}

if (strlen($errormessage)<1) {
$username = $_POST['username'];
$password = $_POST['pw'];
$fname = $_POST['fname'];
$lname = $_POST['lname'];
$dob = $_POST['dob'];
$gender = 1;
$email = $_POST['email'];
$active = 0;
$kkey = md5(rand(0,10000)) ;
$newsletter = 1;
$admin = 0;
$autobidder = 0;
date_default_timezone_set('UTC');
$created = date("Y-m-d G:i:s");
$dest = "username,password,first_name,last_name,date_of_birth,gender_id,email,active,created,`key`";
$val = "'$username','$password','$fname','$lname','$dob','$gender','$email','$active','$created','$kkey'";
$sql = "INSERT INTO `users` ($dest) VALUES ($val)";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
mysql_close($con);
$url = 'http://premierbid.es/app/webroot/users/register'."?key=".$kkey.'&username='.$username;
$content = 'Please click the following link to confirm : '.$url;
$sender = "noreply@nevergone.eu"; //senders e-mail adress
$subject = "Confirm swoopo registration"; //subject
$header = "From: ". $sender . " <" . $sender . ">\r\n"; //optional headerfields
ini_set('sendmail_from', 'noreply@nevergone.eu'); //Suggested by "Some Guy"
mail($email, $subject, $content, $header); //mail command :)
$errormessage = 'An activation link has been sent to '.$_POST['email'].'<br />Please check your email';
}
}
else {
$errormessage = "Invalid email address".'<br /><br />';
}
}

}

echo $errormessage;
}
?></span>
<form action="" method="post"><table width="200" border="0">
<tr>
<td>*Username:<br /><span style="font-size:7.5px;">Minimun 6 characters</span></td>
<td><input type="text" name="username" value="<?php echo $_POST['username'] ?>"/><br /><br /></td>
</tr>
<tr>
<td>*Password:<br /><span style="font-size:7.5px;">Minimun 6 characters</span></td>
<td><input type="password" name="pw" /><br /><br /></td>
</tr>
<tr>
<td>*Confirm Password:<br /><span style="font-size:7.5px;">Minimun 6 characters</span></td>
<td><input type="password" name="pw2" /><br /><br /></td>
</tr>
<tr>
<td>First name:</td>
<td><input type="text" name="fname" value="<?php echo $_POST['fname'] ?>"/><br /><br /></td>
</tr>
<tr>
<td>Last name:</td>
<td><input type="text" name="lname" value="<?php echo $_POST['lname'] ?>"/><br /><br /></td>
</tr>
<tr>
<td>*Email:<br /><span style="font-size:7.5px;">Minimun 6 characters</span></td>
<td><input type="text" name="email" value="<?php echo $_POST['email'] ?>"/><br /><br /></td>
</tr>
<tr>
<td>Date of birth:</td>
<td><input type="text" name="dob" value="<?php echo $_POST['dob'] ?>"/><br /><br /></td>
</tr>
<tr>
<td>&nbsp;</td>
<td><input type="submit" name="submit" value="submit" /></td>
</tr>
</table>
</form>





</div>
</div>
</div>

<div class="col2">
<h3 class="heading"><?php __('Already a Member?');?></h3>
<p><?php echo sprintf(__('If so you may want to %s now.', true), $html->link(__('login', true), array('action'=>'login')));?></p>

<h3><?php __('Forgotten Your Password?');?></h3>
<p><?php echo sprintf(__('Click here to %s.', true), $html->link(__('reset your password', true), array('action'=>'reset')));?>
</p>
</div>
</div>

Editado

uso cakephp para mi web

eh estado revisando el código y parece estar bien, supongo que el erro vendrá de algún archivo dependiente.

creo que te va a tocar hablar con los de soporte en cakephp... suerte!

Gracias pues.. y como puedo sacar el error? que me diga cual es el error de la pagina

puedes probar con error_reporting, mira la documentación es fácil http://php.net/manual/es/function.error-reporting.php