Well, I have not seen that error before.
First, I’d make sure you have Scenario 1 totally un-deployed before testing scenario 2.
Next, make sure your 2nd Orchestration is returning the message. (i.e. do you get this error after 60 or 90 seconds?).
Last, have you tried exposing the Orchestration as a Web Service or are you just exposing the schemas?
Best of luck and please keep us updated if you get it working.