I know this thread is most of a year old, but for posterity’s sake I think I know what your problem is, having recently gone through a similar situation myself. I don’t think you attached an integrator to your PhysicsManager. To copy a few lines out of of tah’s big reply:
LinearEulerIntegrator *lei = new LinearEulerIntegrator();
mPhysicsManager.attach_linear_integrator(lei);
Physics simply does not work in Panda3d unless your physics manager has an integrator attached to it AND do_physics is called every frame.