Error: Unable to load DLL 'SQLite.Interop.dll'

I am working on this tutorial here: http://producthelp.sdl.com/SDK/TranslationMemoryApi/3.0/html/65d6719b-b85e-46a4-bec0-86606e8e0676.htm

I have made some progress but now I am getting this error:

Sdl.LanguagePlatform.Core.LanguagePlatformException: Unable to load DLL 'SQLite.Interop.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
   at Sdl.LanguagePlatform.TranslationMemoryApi.AbstractLocalTranslationMemory.get_Setup()
   at Sdl.LanguagePlatform.TranslationMemoryApi.FileBasedTranslationMemoryLanguageDirection.get_SourceLanguage()

I see the file 'SQLite.Interop.dll' in various places on my machine and tried adding it as a reference, but Visual Studio won't all that.

It seems like this is a common error based on this Stack Overflow question: https://stackoverflow.com/questions/13028069/unable-to-load-dll-sqlite-interop-dll

Any ideas?

Gary