Then, if you're getting a blank page, it's probably because of a fatal error. Could you please make sure that your PHP configuration enables you to see errors and if not, edit your php.ini file and search for the string parameter display_errors.
This parameter should be turned On : display_errors = On.
If it's not the case, please edit your php.ini file, modify this line, save your file and try again.
You should now see the error message instead of a completely blank popup.
If you don't know how to modify your php.ini you should ask your hosting company as the method varies from one to another.