Did it cancell when Pee-Wee was arrested???
http://www.mugshots.net/pee_wee_herman/
<<< he was arrested (haha) during 1991, when he's show was cancelled.
I'm 90% positive that Paul Reubens ended the show sometime in 1990, and there was enough episodes to have it run until 1991, and after the shows finale, it was supposed to come back on in re-runs, but after the incident, CBS opted not to bring it back on.
*~*Paul Reubens = Vsya Moya Lyubov'*~*