This worked for me too.
I have Creamware/SonicCore Scope 5.0 installed here, and had no problems using that ASIO driver until tonight. I usually use Reason as a Rewire Slave, but I wanted to try Reason with my new Focusrite Scarlett interface. Not sure if it's Scope's ASIO driver or Focusrite's, but the workaround of the two prf files worked...
If I do narrow down the culprit, I'll post back here.