Simple, download the most recent version of Blender. Download Blender 2.49b to someplace else; you're only going to use it for exporting. Download the .dts exporter for 2.49b from the Blockland webstie. Then just model whatever the hell you want in the most recent version, and when you want to export it to a .dts save it and open it in 2.49b, make sure everything is intact (it should be) then export it. This is what I do and I've never had any issues.