if you are getting blank pages, I'm guess the 'display_erors' is set to false, and there is an error on the page. Use
$ php -l webpage.php
to test for errors on the page. (If this doesn't run, install php-cli (ie sudo apt-get install php-cli). This will give you the the error and line location of the erorr, if any. Hope this helps. If there aren't any errors, create a new php file with the following:
Code:
<?php
phpinfo();
?>
Save the above as info.php, and load it. If it displays information about your PHP configuration, then your PHP is setup currectly. (Delete the file after you are done with it, as it gives a lot of information away, and could fall into the wrong hands, etc).