The latest versions of my tools install TrainzMeshImporter automatically.. 
However, the TMI does require C++ runtime files that must be downloaded from Microsoft.  The instructions and web address are in my progams' help system.  I am not licensed to supply these files, so you must get them from MicroSoft.  It would be much easier if Auran/N3V made the TMI completely stand-alone.
I have three published programs that require the TMI:
PM2IM, QuickShadows, and Attachment Maker.