midicmd="abc2midi /Users/jc/w/tmp/Tune-17013-B17.abc -v -o /Users/jc/w/tmp/Tune-17013-B17.midi >>/Users/jc/w/tmp/Tune-17013-get.log 2>&1" returned status 256.

Error exit status 256; here are some files to check:
[P=get.cgi V=1/1 B=0 scale=0.60 512x512 ]
filesizedescription
Tune-17013-B17.abc 692 ABC music file with the extracted tune(s)
Tune-17013-get.log 2998 Log file, useful mostly for debugging
These files should be available for 24 hours.