improved error message
improved error message

ketchupok/csound,ketchupok/csound,csound/csound,csound/csound,csound/csound,csound/csound,csound/csound,ketchupok/csound,ketchupok/csound,csound/csound,csound/csound,ketchupok/csound,ketchupok/csound,ketchupok/csound,csound/csound,ketchupok/csound,ketchupok/csound,csound/csound,ketchupok/csound,csound/csound