The failing command is gs, with the message:
DEBUG: no psname was provided. GNU Ghostscript 7.07: Unrecoverable error, exit code 1
The printer has a really old postscript interpreter that can't handle the file directly. I can't find a resolution. It appears to be a problem with fonts, but I don't know what the solution might be.
I've attached the cups debug output if that is useful.