WSOD

I am using drigg and have installed it as per instructions from here http://blog.itechtalk.com/2009/drigg-6-express-setup-drupal-610/. It is express install. Everything went smoothly and since I am using drupal for some time, it didn't took me lot of time to configure everything. But when I am trying to add feeds in RSS Drigg feed reader, I am getting WSOD (which are really annoying as u don't know what caused it)

As soon as I hit submit after filling Drigg RSS feeder entries, I get blank page , I get black white page. anyone has any idea what is causing this ? I have not added any category from feed aggregator as I my site categories are getting shown in Drigg Rss Feeder drop down.