Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/PDF/_.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-8901-_.ps) >>/Users/jc/w/tmp/Tune-8901-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/PDF/_.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-8901-24FavouriteDances_1783_Straight.abc 175 ABC music file with the extracted tune(s)
Tune-8901-24FavouriteDances_1783_Straight.ps 6 PostScript
Tune-8901-24FavouriteDances_1783_Straight.txt 175 Plain-text file with the extracted tune(s)
Tune-8901-_.abc 137 ABC music file with the extracted tune(s)
Tune-8901-_.ps 6 PostScript
Tune-8901-_.txt 137 Plain-text file with the extracted tune(s)
Tune-8901-get.log 11945 Log file, useful mostly for debugging
Tune-89011-get.log 4135 Log file, useful mostly for debugging
Tune-89013-get.log 3469 Log file, useful mostly for debugging
Tune-89015-get.log 3384 Log file, useful mostly for debugging
Tune-89018-get.log 4691 Log file, useful mostly for debugging
Tune-89019-get.log 5080 Log file, useful mostly for debugging
These files should be available for 24 hours.