fix silent failures when rt cannot be assigned

fixes #350 

We attempt to print out an error when RR is not assigned, but we never reach that part of the code with the current implementation. This pull request ensures that an error is printed to the user. It also defaults to cfs when RR fails. This allows xterms to still be opened in each host.
I don't think you want to print this message in all of the `else` cases.