Hi Steve, let me know if these steps work for you:
1. Do you have C++ Source code in your UE4 project? If so, load your solution file in Visual Studio and proceed to step 7, otherwise keep reading:
2. Load your project in the UE4 Editor
3. Click File -> Add Code to Project
4. Leave "None" Selected and click Next.
5. Leave the fields at default and click Create Class.
6. Click yes when asked if you'd like to edit the code now.
7. Make sure your project configuration is set to "Development."
8. Click Build->Build Solution and wait for your project to compile. It should also compile in the substance library.
9. Close Visual Studio and Reopen your project in the UE4 Editor
10. Click Launch
I know it's more than a few steps, but let me know how it goes!