It's resolved, thanks. It appears to have been because of an old version of CSound, although why it worked one day and not the next remains a mystery. Fixed by downloading Csound 5.
I ought to have notified the list when it was resolved, but my message never echoed back to me. I had hoped it just disappeared into the net-ether... ;)
Rather than "/usr/local/bin/csound" for the csound executable, it just says "csound".
What version of Csound are you using, and what version of OSX?
Also, could you check in the program options ("Preferences",
accessible from the blue menu) and see if you have
"/usr/local/bin/csound" for the csound executable. And do you have
any project example that would show the behavior?