pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-37737-CowBoysJig.ps) >>/Users/jc/w/tmp/Tune-37737-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/ryan-cole/Tunes/CowBoysJig.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-37737-CowBoysJig.abc 418 ABC music file with the extracted tune(s)
Tune-37737-CowBoysJig.ps 34226 PostScript
Tune-37737-CowBoysJig.txt 418 Plain-text file with the extracted tune(s)
Tune-37737-get.log 4514 Log file, useful mostly for debugging
These files should be available for 24 hours.