Civ4 complete is installed in C:\games\Civ4 Complete\
BTS is thus in: C:\games\Civ4 Complete\Beyond the Sword\
I installed the mod in C:\games\Civ4 Complete\Beyond the Sword\mods\Tech Tree Editor\
(I first installed it to My Games\Beyond the Sword\Mods\Tech Tree Editor\ with the same result.)
Ah, that might be the problem. Give me a sec and I'll give you a fix