Blender not exporting correctly


I created a simple model consisting of 3 basic meshes(untextured).
First I created a cube, copied it and placed the copy a bit left of it and then put a 3rd cube on top of both (so it looks like an arc). Now I wanted to try the exporter and exported it as .obj. When I load the object in another program, it is broken. In my case only the top cube showed, while the rest was not there. Other formats I tried were also broken.
This was done with Blender 2.49.

Any idea what the problem is?

/edit: Got it working with the newest Blender version.