Who owns Zorro?

While not strictly horror, I'd imagine that there're a fair numbers of readers of this site who also enjoy the swashbuckler genre (Arrrgh, Cap'n Carnacki...?). While prepping my previous item about Marilyn Monroe, this sidebar item in The Guardian also caught my eye:

Filing suit at the US District Court in Los Angeles, Sobini Films and its subsidiary Maroda Inc claim that that they have acquired the rights to Johnston McCulley's 1919 source novel The Curse of Capistrano and plan to install its swashbuckling hero in a sci-fi extravaganza, entitled Zorro 2110. Sony, meanwhile, insists that it owns exclusive licence to develop all Zorro-based material.

First off, lemme say that 'Zorro 2110' sounds, well... lame... but that isn't what really got my attention. What really got me was that you'd think that after 80+ years, Zorro would have entered the realm of public domain and that one could do whatever the hell you wanted with the character. But no, at least not as far as the film industry is concerned. What does constitute reasonable protection of a writer's work (or musician or film maker)? How much protection is afforded them as opposed to their distribution channel: the publishing house, the record label, the movie studio? As someone who dabbles in writing myself, I've released my own stuff under a Creative Commons license. I'd be interested in hearing what others have to say on this...