Move the line
to the line above the part there you multiply the mass with the forces.
In the current state you multiply the forcevalues with a zero mass.
NewtonBodyGetMassMatrix (Body,Varptr Mass, Varptr IXX, Varptr IYY, Varptr IZZ);
to the line above the part there you multiply the mass with the forces.
In the current state you multiply the forcevalues with a zero mass.