ABC and the Carsey-Werner Co. were apparently in such a hurry to tell the world about their renewal of “Roseanne,” they forgot something.Namely, Roseanne Arnold. The network and the show’s production company announced a three-year extension of the series last Friday, calling for 75 more episodes of the high-rated comedy series at a license fee well in excess of $ 2 million per segment (Daily Variety, Feb. 22). However, Roseanne and Tom Arnold — the show’s star and exec producer — are said to have an agreement with Carsey-Werner for just two more years of the series, and sources indicated that the couple hasn’t officially agreed to anything beyond the 1995-96 season. A spokeswoman for ABC said only that the network has a three-year deal with Carsey-Werner and referred talent questions to the production company. Carsey-Werner officials couldn’t be reached for comment but were said to be working to square things away with the Arnolds, who, through a spokesman, acknowledged that they felt the announcement had been premature. If Roseanne Arnold has anything to say publicly about the matter, viewers won’t have long to wait: Arnold, who made headlines by threatening to take her show to another network last spring on “The Tonight Show With Jay Leno,” is scheduled to appear on the NBC show again tonight.