> the "cannot load txx file" error
You get the error because that is not how you load a terrain bitmap. Copy it to the windows clipboard and paste it from the Edit Menu.
> checkpoints ... in ... the right direction
If you did traxx school you'll see there's checkpoint models with arrows on them. Until you become more familiar with traxx, you should think about using those.
> sorry no pictures quite yet.
No test track either.
> is it easier to place models with tracked2?
Some people like it, some hate it. Malibu350 just completed 'toys in the attic' and it was made entirely in traxx. That should tell you something about the capabilities of traxx.
> does it place models like tracked3 and 4 do?
Essentially, yes. The most information on tracked2 track making is right here:
http://cownap.com/~mtmg/tracked2/