Faces of models not fully rendering

I'm completely new here. I know I've seen the solution to this in a tutorial somewhere but I can't seem to find it after replaying through the first 4. I'm using tutorial02 to import a model, and I've changed the source to point to my own sio2 file. I'm just using the default scene in blender and the faces of my cubes are showing up as two triangles, making a square that is half white and half black. I get the same effect if I delete the default cube and add a suzanne. However if I switch back to the tutorial02.sio2 file it renders fine. There must be a setting I'm missing when I export that is basically causing all faces of my model to only render half of the face. Can someone point me in the right direction please?

Convert quads to triangles within blender...

Thanks for the quick response. Worked like a charm.