Polyobject help

So I made a polyobject, and it's there and solid ingame, but the textures that I set for it don't show up. It just sits there, invisible. I set the front middle textures and everything, so why don't they appear ingame? How do I fix this?

Mind supplying the file? We may be able to help better.

Is it a really tall polyobject?

If so, did you set Effect 5 on the linedefs?

The polyobject is 888 units high. I tried checking effect 5 and putting the texture offset at 888, but then the textures were too high up and then the game crashed when I touched the object.

That is a known bug: http://mb.srb2.org/showthread.php?t=33916

Polyobjects are a can of worms, they bring all sorts of problems, from visual glitches to hard crashing the game. This is mostly due to not being functionally complete yet.

About your specific case, I think you should reconsider your original idea. Are you sure there aren't any alternative ways to do what you want in your map?