Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1776/CDfNH1783.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-9014-CDfNH1783.ps) >>/Users/jc/w/tmp/Tune-9014-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1776/CDfNH1783.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-9014-CDfNH1783.abc 146 ABC music file with the extracted tune(s)
Tune-9014-CDfNH1783.ps 6 PostScript
Tune-9014-CDfNH1783.txt 146 Plain-text file with the extracted tune(s)
Tune-9014-get.log 4043 Log file, useful mostly for debugging
Tune-90142-get.log 3256 Log file, useful mostly for debugging
Tune-90144-GentlemansMagazine.abc 154 ABC music file with the extracted tune(s)
Tune-90144-GentlemansMagazine.txt 154 Plain-text file with the extracted tune(s)
Tune-90144-get.log 3324 Log file, useful mostly for debugging
Tune-90145-JohnTreat_GftF2.abc 151 ABC music file with the extracted tune(s)
Tune-90145-JohnTreat_GftF2.pdf 2217 Portable Data Format
Tune-90145-JohnTreat_GftF2.ps 6 PostScript
Tune-90145-JohnTreat_GftF2.txt 151 Plain-text file with the extracted tune(s)
Tune-90145-get.log 5023 Log file, useful mostly for debugging
Tune-90146-get.log 4515 Log file, useful mostly for debugging
These files should be available for 24 hours.