pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-90436-4151.ps) >>/Users/jc/w/tmp/Tune-90436-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Gow/CR12/4151=Lady_Montgomerie-abc2.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-90436-4151.abc 1227 ABC music file with the extracted tune(s)
Tune-90436-4151.ps 41940 PostScript
Tune-90436-4151.txt 1227 Plain-text file with the extracted tune(s)
Tune-90436-get.log 4930 Log file, useful mostly for debugging
These files should be available for 24 hours.