OK, this is not strictly BTB, but it's pretty close. I have recently tried packing all the objects and textures of a new circuit I've created into MAS files as I have done in the past, but the MAS explorer (and I've tried two types: the MAS explorer and the other one with the yellow icon, I'm sure you know the one) freezes half way through and does not create a file with all the objects or textures. Needless to say, it doesn't work in-game. Any ideas? I've tried installing the programs again, to no avail.