While doing so, I noticed within 10 seconds that it was checking for the IP as well, something I didn't intend to do. So I clicked the cancel button. Went to the URL and pressed enter to reload the page.
I clicked on Spam in a post again, unchecked 'check for ip', and run it. About 10 seconds in I gave the following error:
http://dl.dropbox.com/u/693961/Screen shot 2011-02-23 at 3.27.00 AM.png
After quick investigation it appears the posts are indeed all gone. (so I also can't reproduce it).