It's not a pretty story, I'm afraid.
Due to the actions of another publisher (and I'm not naming names, so don't ask), Adamant has been contacted by the General Counsel for Edgar Rice Burroughs, Inc. -- this publisher sent them a copy of the preview, and they're concerned about the similarities to the Burroughs works -- which are only Public Domain in the US.
Adamant is currently attempting to assure ERB Inc. that the similarities are only to things which are common to the Planetary Romance genre as a whole, and present in the works of of Jack Vance, Lin Carter, Michael Moorcock, Leigh Brackett, and dozens of other authors as well. The rights of the Burroughs estate have not been, and will not be, violated -- even on those works which have been afforded public domain status in the US (A Princess Of Mars, Gods Of Mars, Warlord of Mars, Thuvia; Maid Of Mars, and The Chessmen Of Mars, specifically).
Adamant preferred to create our own original setting in the style of the dozens of existing works in the Planetary Romance genre, rather than any single author.
The problem here is this -- I am 100% sure of our legal standing...however, if ERB Inc. decides to go to court, Adamant simply cannot afford to fight. So, right now, everything is on hold while I try to assure them that their rights are not being challenged.
We're a very small company -- and right now, we're not willing to throw additional work into a release that may have to pulled immediately in the event of a legal battle, caused by the maliciousness of another publisher. Once the discussion with Edgar Rice Burroughs Inc. has reached some kind of resolution, Adamant will make the decision regarding how to proceed.