I know this response comes several years too late to help, but perhaps a reply will help another forum-searching problem-solver.
For Powerpoint 2007, on the "View" tab of the toolbar, select "Notes Page" and look for a reference to your slide number in there. Then delete it, and it should disappear from your published presentations.
I had an issue with copyright info appearing in my published notes tab, and I found it on the "Notes Master" first, but deleting it there didn't delete it from the individual notes slides. Had to do that by hand.
Hope this helps somebody. It was a frustrating afternoon for me.