I tried to use the trees dilivered with the bootcamp demo in my project, but the trees are just purple without any textures on it.. I did imported the textures as well.. What could be the problem?
Sounds like you didn't export the shaders it was using (or it lost the asset link to them)
Try readd the soft vegetation shader to them then the textures, or use unity's Export (right click tree > export) functionality to move them instead