pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-84407-CR20.ps) >>/Users/jc/w/tmp/Tune-84407-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/abc/Contra/CR20.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Tune-84407-CR20.abc 2438 ABC music file with the extracted tune(s)
Tune-84407-CR20.ps 47420 PostScript
Tune-84407-CR20.txt 2438 Plain-text file with the extracted tune(s)
Tune-84407-get.log 4384 Log file, useful mostly for debugging
These files should be available for 24 hours.