Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1758/JohnFrench.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-9641-JohnFrench.ps) >>/Users/jc/w/tmp/Tune-9641-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1758/JohnFrench.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-9641-JohnFrench.abc 147 ABC music file with the extracted tune(s)
Tune-9641-JohnFrench.ps 6 PostScript
Tune-9641-JohnFrench.txt 147 Plain-text file with the extracted tune(s)
Tune-9641-get.log 4066 Log file, useful mostly for debugging
Tune-96417-get.log 4957 Log file, useful mostly for debugging
Tune-96418-Goulding_SSEIFA_v3.abc 155 ABC music file with the extracted tune(s)
Tune-96418-Goulding_SSEIFA_v3.ps 6 PostScript
Tune-96418-Goulding_SSEIFA_v3.txt 155 Plain-text file with the extracted tune(s)
Tune-96418-get.log 8257 Log file, useful mostly for debugging
Tune-96419-get.log 5729 Log file, useful mostly for debugging
These files should be available for 24 hours.