pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-77721-CottonEyedJoe.ps) >>/Users/jc/w/tmp/Tune-77721-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/abc/Contra/CottonEyedJoe.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-77721-CottonEyedJoe.abc 1816 ABC music file with the extracted tune(s)
Tune-77721-CottonEyedJoe.ps 34692 PostScript
Tune-77721-CottonEyedJoe.txt 1816 Plain-text file with the extracted tune(s)
Tune-77721-get.log 5009 Log file, useful mostly for debugging
These files should be available for 24 hours.