Can't get Cytoskeleton to load.

Rhino 6.

I have Plankton v0.4.2 from https://github.com/meshmash/Plankton/releases (I also tried Plankton v0.3.0). Using Exoskeleton2_150904.zip. All of these were plopped into Grasshopper/6/Libraries:

On launching Grasshopper, I get the following error messages:

When Grasshopper loads, Cytoskeleton is missing.

I had this problem before, on another computer, but the solution I was given (copying Plankton.gha to PlanktonGh.dll) isn't working.  I see that this has been brought up before, but I don't see a solution (I did try Plankton 3.0)

http://www.grasshopper3d.com/group/exoskeleton/forum/topics/cytoske...