pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7463-Gow-CR-abc1.ps) >>/Users/jc/w/tmp/Tune-7463-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Gow-CR-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
Coll_74632.log 523180 Log file, useful mostly for debugging
Coll_74638.log 252014 Log file, useful mostly for debugging
Tune-7463-Gow-CR-abc1.abc 389814 ABC music file with the extracted tune(s)
Tune-7463-Gow-CR-abc1.ps 3967811 PostScript
Tune-7463-Gow-CR-abc1.txt 389814 Plain-text file with the extracted tune(s)
Tune-7463-get.log 253476 Log file, useful mostly for debugging
Tune-74632-get.log 4735 Log file, useful mostly for debugging
These files should be available for 24 hours.