SmartAssembly cannot find System.Runtime

I'm brand new to SmartAssembly 8. Currently trying to obfuscate and existing project (that creates a DLL). As soon as I select the DLL to obfuscate, I get this message.
Getting this message:

How do I fix this? How do I point SmartAssembly to the right dependency?
Getting this message:

How do I fix this? How do I point SmartAssembly to the right dependency?