Add Framevariables error in kinematicsolver class

i am using 3 prr delta robot, i am modyfying on delta robot library, i have an error of the base path must specify the full path to a frame port of a simscape multibody block in the model, if the path refers to a frame port on a subsystem block, the port name must match the name of the corresponding port connection.... the name is the same and also the path, the problem i think is in creating the base and follower in my model, i donot know what is wrong???