Most likely the entire site is creating a zip file that is to big, please send only the registration and the login page for now in a zip archive.
when a blank page displays, it is because a php error is occurring, we will need to know the text of the error to debug it.
to get the error text add the following code at line 1:
<?php
error_reporting(E_ALL);
ini_set('display_errors','on');
?>