I am not familiar with the MAC environment but I assume the procedures are relatively the same under a Windows OS.  When installing V4, there is an primary initialization to prep the model for morph channels.  Then install the Morph++ pack and rerun the initialization again to prep the model to receive the pack.  Load a new V4 into the scene and inject the morphs++.  Everytime a new morph pack is introduced, the initialization must be rerun.  To check if the initialization had taken, load a base V4 into the scene and look at the Parameters tab for a new channel entitled Morph++.  Everything should work after injecting the pack.  Do not attempt to add morphs to a V4 model already saved into your Library or .pz2 scene prior to installing the Morph++ pack, those models would not have the appropriate channels established to accept the pack.