midicmd="abc2midi /Users/jc/w/tmp/Tune-25955-session.abc -v -o /Users/jc/w/tmp/Tune-25955-session.midi >>/Users/jc/w/tmp/Tune-25955-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-25955-get.log 16642 Log file, useful mostly for debugging
Tune-25955-session.abc 538 ABC music file with the extracted tune(s)
Tune-25955-session.malt 0 Musical Instrument Digital Interface, alternate name for midi format
Tune-25955-session.midi 0 Musical Instrument Digital Interface, electronic version of the tune(s)
Tune-25955-session.txt 538 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.