try to uninstall all (and for safety also delete manual after the uninstall the blender folder), install python first, blender and after blender the rest. Already after the Blender install there should be more than 3 import options.
I also work with 2.46 and the 2.2.10 scripts, but i only make units, so no idea if it still works with leaderheads. If you want to use the script version in this tutorial described it would be better if you search for an older Blender version (2.43)