Interesting – blank screen WP 3.7.1

Hi,
Is it the entire admin dashboard goes blank white? or the theme you duplicate is all white?
Are you able to check your error log? If so, could you see if anything is anything in there that is related to the plugin. You can do a search for duplicate-theme and that should narrow down your search.
Thank-you for reporting your issue. We would like to get this plugin working for your network.

It sounds like a White Screen of Death. If you enable WordPress debugging in wp-config.php, change the line:
define(‘WP_DEBUG’, false);
to:
define(‘WP_DEBUG’, true);
you should see more info on what is causing the error.