pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-22421-Saint_Martins.ps) >>/Users/jc/w/tmp/Tune-22421-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Playford/Saint_Martins.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-22421-Saint_Martins.abc 617 ABC music file with the extracted tune(s)
Tune-22421-Saint_Martins.ps 33787 PostScript
Tune-22421-Saint_Martins.txt 617 Plain-text file with the extracted tune(s)
Tune-22421-get.log 4510 Log file, useful mostly for debugging
These files should be available for 24 hours.