Walty, I forgot to mention in my post that I was not referring to your avatar or your television show specifically, but was just answering the question you asked about whether it was okay to have avatars from TV shows. But now that you ask, if the television show your avatar represents is sinful, then it would be scandalous to use it because it would remind others of the sins in the show and would make people think you watch and enjoy a sinful show.
I have never watched the office, so I cannot say if it is sinful or not, but I will try to answer your question anyway. If there are actresses dressed immodestly on the show and you look at them with lust, you could be guilty of mortal sin, if there are any dirty jokes and you laugh at them and you continue watching the show knowing that there will be more dirty jokes, you may be guilty of mortal sin. If there is any blasphemy or use of the Lord's name in vain and you laugh and continue to watch the show despite the blasphemy or use of the Lord's name in vain, you could be guilty of mortal sin. If any of the characters hold any erroneous opinions or have bad morals, and you are influenced by these erroneous opinions and bad morals, endangering your faith, and you continue to watch the show, you may be guilty of mortal sin. If there are immoral characters who commit sins or pretend to commit sins on or off the screen and you sympathize with them and vicariously enjoy these real or simulated sins you may be guilty of mortal sin. Of course, I have never seen the show so I do not know if it has any of these elements or not.