plug-in loading problems after Geom Gym update?

Just updated to the latest Geometry Gym, and something seems to have broken loading many of my GH plug ins, including kangaroo, shortestWalk, and 4d-noise.... Here's an example error message:

  Exception System.NotSupportedException:   Message: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.
An exception occured during GHA assembly loading:  Path: C:\Program Files (x86)\Rhinoceros 4.0\Plug-ins\Grasshopper\Components\Kangaroo0051_WIP.gha  Exception System.IO.FileLoadException:   Message: Could not load file or assembly 'file:///C:\Program Files (x86)\Rhinoceros 4.0\Plug-ins\Grasshopper\Components\Kangaroo0051_WIP.gha' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)

The microsoft help page is a bit opaque to me. Anyone have an idea? It may not have anything to do with GeomGym, either, I've also been messing around a bit with Reflector. 

Thanks,

Andrew