Unless there was an agreement between the writers and the Dojo/Psylum, the rights to the material are still the authors'.
Legally, you can archive the material on your computer for your own use (Fair Use Act) but can't distibute it. It does not seem likely that anyone would mind you doing this, though, since there was no official negative response (that I'm aware of) to Mike Flores's call to archive the old Dojo articles, so long as no one is making any money off it.
Worst case scenario is that you can archive the files yourself, the "share" them, á la Napster, with anyone else, who can make their own Fair Use copies.