Fixing Back Exo solid model on Mocap Model

Hi, I am carrying out simulation of Lower Limb Exoskeleton in a Mocap Model , for which I have created a waist support system in solidworks which is a single segment and has 6 DoFs. This model was converted into Anyscript and called in Mocap Model.
Now in order to perform kinematic analysis, I have constraint its 6 Dofs by using AnyKin linear for constraining its 3 linear motion and ANykin Rotational for constraining its 3 rotational motion. I have fixed the solid model centre node with the node 'hipjointcentreTD' on human model.
With this understanding I was able to run kinematic analysis successfully but while running the inverse dynamic analysis, error pops up : ERROR(OBJ.MCH.KIN2) : D:/S..l/P..S/L..r/S..n/H..)/M..l/AnyMocapModel.any(94) : InverseDynamicStudy : Model is kinematically over-constrained : Position analysis failed : 6 unsolvable constraint(s) found

Kindly help me in resolving this error.