Victor Kubicek and Derek Anderson currently hold the rights to Terminator 4. According to Variety, they have had to sue MGM for interfering in the planned distribution of the proposed sequel.
The Halcyon Company, which is run by Kubicek and Anderson, acquired the rights to Terminator 4 in May. According to the complaint, filed in L.A. Superior Court on Wednesday, MGM claimed it had acquired an exclusive 30-day negotiation window for "T4" in the 1990s Orion Pictures bankruptcy. Basically, MGM is saying that they have the rights to put the movie into theaters, but Halcyon would rather distribute the film through a different company.
What does that mean for us, the audience? It means that we won't be able to see another Terminator film until this mess is cleared up in court. Oh, well. There's always The Sarah Connor Chronicles. Hmm, did that even make it to a series?