If he did not go, why?
Just a guess. He's up for tenure, and there's some concern about his relationship to the 2nd place cartoon in the Iranian cartoon contest, as well as his use of his title, Professor, in some of his anti-semitic activities. Turning up in Iran as Professor Finkelstein from DePaul might embarass DePaul, who should be ashamed of hiring Finkelstein knowing his views, and harm his tenure bid.