Looks like some of the frames need a rotation. I'm not sure about what mechanism you are trying to model, but right now, the three bars can rotation in the x-y plane, but the prismatic joint is trying to make one end to move in the z-direction, i.e. out of the x-y plane. I suspect the prismatic joint should be constraining the motion in the x or y direction instead.
I took out the 1D Simscape part and kept only the Multibody. After adding some rigid transform blocks to align the motion direction, the model will at least assemble and move. See attached. Not sure whether that's what you intended. Here is a picture.
