Razmatazed - 12:53 am on Jan 31, 2013 (gmt 0)
I had the same problem. Inside Site Explorer it was displaying a bunch of folders with ?'s at the end. When I clicked into them I realized that Bing was marketing them as unique pages and diluting my SE Results. Realizing my url parameters were not set up. I quickly migrated the settings from Google Webmaster over :)
Hope this helps!