Was Rhino WIP 6.0 support removed at some point between the Feb 2015 post and the May 2015 release of Zoo 6?
The link leads to
As installed, Help, About Zoo, Version 6.0.15149.9391, 5/29/2015
The Add Licence dialog, Product Type dropdown
does not list Rhino 6 WIP,
Rhinoceros 6 is listed, but the form
of course will rejects our RH6B WIP keys.