Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/Graded1/JohnFrench.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4906-JohnFrench.ps) >>/Users/jc/w/tmp/Tune-4906-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Graded1/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-4906-JohnFrench.abc 150 ABC music file with the extracted tune(s)
Tune-4906-JohnFrench.ps 6 PostScript
Tune-4906-JohnFrench.txt 150 Plain-text file with the extracted tune(s)
Tune-4906-get.log 4082 Log file, useful mostly for debugging
Tune-49061-get.log 10099 Log file, useful mostly for debugging
Tune-49062-get.log 4390 Log file, useful mostly for debugging
Tune-49064-get.log 9321 Log file, useful mostly for debugging
Tune-49065-get.log 9535 Log file, useful mostly for debugging
Tune-49067-get.log 3917 Log file, useful mostly for debugging
Tune-49068-get.log 4507 Log file, useful mostly for debugging
Tune-49069-get.log 4555 Log file, useful mostly for debugging
These files should be available for 24 hours.