Okay - I think I've solved this one on my own. When i originally installed DarkPhysics - it installed into the folder for the trial version I had. I moved the darkphysics.dll, but there were others - nxcooking.dll, nxcharacter.dll, nxextensions.dll, and PhysXLoader.dll. I moved these to the plugins-licensed folder and all seems well - I can run the demos at least. Now learning how to use it will be another story. Any hints, tricks, or man don't do that advice is welcome.
'Yeah...I'm gonna' have to ask you to come in on Saturday. That'd be great.'