I had a problem that sounds the same. A little while ago, I installed Clockscreen, and it "came with" 12 blank icons. I could delete the icons, but re-springing would bring them all back. I was thinking about taking apart the .deb file to see where it was hiding the buggers, but ended up manually copying the Clockscreen theme to a temp folder, removing Clockscreen, and moving the theme back. Voila! No more extra icons.