Opening a .rsmn file


I am working through chapter 10, and saving and loading seems to be working fine. However, if I attempt to open a .rsmn file without having the RaiseMan app running, I get this error:

Application Specific Information:
objc[23484]: garbage collection is OFF
*** Terminating app due to uncaught exception 'UnimplementedMethod', reason: 'readFromData:ofType:error: is unimplemented'
*** First throw call stack:

When opening this file with the App running, I get no error. Could it be because RaiseMan isn’t in the /Applications folder?

Thank you!