If you find a white screen or error 500 that usually means something has triggered a PHP error, but errors are hidden on your server. To find out the cause of the error you have two choices:
WP_DEBUGmode and view the page again
WP_DEBUG involves editing your
wp-config.php file and changing, or adding if its not there:
define( 'WP_DEBUG', true );
When this is done, a more useful error message should be shown. Most of the time this contains the name of the plugin and the line number causing the issue allowing you to act.