Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/misc/blank.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4063-blank.ps) >>/Users/jc/w/tmp/Tune-4063-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/misc/blank.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-4063-blank.abc 142 ABC music file with the extracted tune(s)
Tune-4063-blank.ps 6 PostScript
Tune-4063-blank.txt 142 Plain-text file with the extracted tune(s)
Tune-4063-get.log 11720 Log file, useful mostly for debugging
Tune-40630-get.log 7709 Log file, useful mostly for debugging
Tune-40631-get.log 12910 Log file, useful mostly for debugging
Tune-40636-get.log 10075 Log file, useful mostly for debugging
These files should be available for 24 hours.