Actually, the US trademark was being held by the former owners of LibLime (Metavore, Inc) in trust for the community. It was used as a bargaining chip against the wishes of the community in the acquisition of LibLime by PTFS in 2010.
The community really got riled up about this in 2010, and all other community trademarks and IP were transitioned to HLT ownership as stewards of the community IP. They own the current domain (http://koha-community.org) and the French trademark (the French company, Biblibre, was holding the French trademark in safekeeping for the community, and paid to have the trademark transferred to HLT's control). There were talks in 2010 of PTFS "allowing" the community to "use" the koha.org domain under their supervision, but it was clear that they wanted editorial control over the site and so it was decided to abandon koha.org.
The NZ trademark fracas has been going on for a solid year now, Metavore (LibLime) had filed for the trademark in NZ not more than a few weeks before they sold themselves to PTFS. PTFS could have chosen to withdraw the application, but chose not to. Joann Ransom, director of HLT explains it all on Radio NZ quite clearly: http://ur1.ca/5zz67
The line PTFS gives is that the trademarks were purchased from LibLime who bought them fair and square from Katipo - which is fair, they did. But they were allowed to register trademarks with the understanding from the community that the assets would be held in good faith, and they have not been - they have been hijacked.
Koha is a gift that HLT gave libraries the world around, and PTFS/LibLime has taken undue advantage of that gift, abusing the community they purport to be a part of.