There is a multitude of discussion about collisions on the forum, but I haven’t found a solid post about using CollisionHandlerFloor. Could someone run me through the process of using it? 
What exactly are you trying to do with it?
Are you trying to make a model “walk” over a mesh you made in something like blender? I accomplished this with Bullet if you’re interested in that.
I got it working, I wasn’t exporting collision geometry using YABEE, but I am interested in how you accomplished it with bullet!