http://www.tvshowsondvd.com/newsitem.cfm?NewsID=2400
"Long negotiations with the rights owners of the title song has caused delays in getting the third season released. The two parties weren't able to negotiate for the use of the theme song for season 3, even though they had done so on the previous releases (two "best of" and two season sets). Columbia TriStar decided to push ahead with the release of season three, since they knew fans would choose the set in some form over no set at all. Columbia TriStar assures us that the music substitution will be clearly marked on the packaging."