Thread:Extension talk:Nuke/Search by IP does not work?

Hi, I am using MW 1.21. Some spammers created lots of spam pages (I allow anonymous user to create pages but disallow creation registering new users). I wanted to use Nuke to mass delete those pages. However, when I put in the spammer's IP (everything else is default) in Special:Nuke, I see the message saying no recent contributions were found for this IP. If I use Special:RecentChanges, I can surely see those spam pages. Am I doing something wrong?

Thanks.