pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-87041-4102-Block_Jock.ps) >>/Users/jc/w/tmp/Tune-87041-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Gow/CR12/4102-Block_Jock.abc1.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-87041-4102-Block_Jock.abc 1591 ABC music file with the extracted tune(s)
Tune-87041-4102-Block_Jock.ps 45785 PostScript
Tune-87041-4102-Block_Jock.txt 1591 Plain-text file with the extracted tune(s)
Tune-87041-get.log 4597 Log file, useful mostly for debugging
These files should be available for 24 hours.