What kind of material do you put on the walls? How does the UV-map look?
Would you be able to send me the obj as well, so I can have a look?
Just send it at bantha@renderosity.com and I will have a look too. Normaly, Poser does not have problems with triangles, in my experience.

A ship in port is safe; but that is not what ships are built for.
Sail out to sea and do new things.
-"Amazing Grace" Hopper

Avatar image of me done by Chidori.