White modal with spinning bar - nothing more

Hi, So I installed Moderation, and it's network activated. I then go to a post, leave a comment. Then I click 'report this comment'. The screen dims and a modal box appears with a spinning bar. Nothing else. I'm never asked why, or for an email address or anything else. Running WP 3.1 as a Network install (multisite). This happens in IE. In Firefox the screen dims, a white modal appears with the title 'Report this comment' with an X but nothing else on the box.