Steve,
I think I have repro'd your error by removing the Reference Assemblies.
The samples available on our website do not have the Essentials Reference Assemblies added to the project. This is to require users to download the CTP and install it on their system. It sounds like you've done all that. The key is though when you open the Sample in VS or Blend you must add the Essentials .dll's to the project before building it.
To add reference assemblies in Visual Studio:
1. Load the Sample project by opening Carousel3DSamples.csproj
2. In the Solution Explorer in VS right click References and select Add Reference
3. In the box that pops up select the .NET tab then select IdentityMine.Windows and IdentityMine.Windows.Essentials and select OK. This will add the correct .dll's to the project.
4. Build and Go
To add reference assemblies in Blend:
1. Load the Sample project by opening Carousel3DSamples.csproj
2. On the Project tab under Files right click on References and select Add Reference
3. In the box that pops up browse to C:\Program Files\Reference Assemblies\IdentityMine Blendables\Essentials Mix\v1.0\ and select IdentityMine.Windows and IdentityMine.Windows.Essentials and select Open. This will add the correct .dll's to the project.
4. Build and Go
This should build the samples correctly. Let me know if this ends up not being the problem and we'll look further into it.
Thanks!
Kurt