pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-79439-NewPetronella.ps) >>/Users/jc/w/tmp/Tune-79439-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/abc/program/event/20161113/NewPetronella.abc

Error exit status 256; here are some files to check:

[P=get.cgi V=1/1 B=0 scale=0.60 512x512 PNG]
filesizedescription
Tune-79439-NewPetronella.abc 710 ABC music file with the extracted tune(s)
Tune-79439-NewPetronella.ps 37886 PostScript
Tune-79439-NewPetronella.txt 710 Plain-text file with the extracted tune(s)
Tune-79439-get.log 4395 Log file, useful mostly for debugging
These files should be available for 24 hours.