pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-35951-SwallowsTailThe.ps) >>/Users/jc/w/tmp/Tune-35951-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/ryan-cole/Tunes/SwallowsTailThe.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-35951-SwallowsTailThe.abc 674 ABC music file with the extracted tune(s)
Tune-35951-SwallowsTailThe.ps 37912 PostScript
Tune-35951-SwallowsTailThe.txt 674 Plain-text file with the extracted tune(s)
Tune-35951-get.log 5199 Log file, useful mostly for debugging
These files should be available for 24 hours.