I can't use modern static objects

[TheGreatCthulhu]

Hm... I'm guessing that the person who created white night simply used plane primitives in conjunction with those texture files, and not custom models. More precisely, it's the material (*.mat) files that were used (which in turn reference those jpgs & tgas) - the folder contains a bunch of them. (You can check this by loading a White Night map.)

In the editor, click on the Primitives button, and create a plane (select a mat file first), then place it and rotate it as necessary, to use as floor, wall or ceiling.

Edit: I checked - yup, it's just planes. Tip: when selected, go to the plane tab to adjust the tiling of the material.