Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/ECPMH/Nelson.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-1845-Nelson.ps) >>/Users/jc/w/tmp/Tune-1845-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/ECPMH/Nelson.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Coll_18452.log 154547 Log file, useful mostly for debugging
Tune-1845-Nelson.abc 144 ABC music file with the extracted tune(s)
Tune-1845-Nelson.ps 6 PostScript
Tune-1845-Nelson.txt 144 Plain-text file with the extracted tune(s)
Tune-1845-get.log 3988 Log file, useful mostly for debugging
Tune-18451-get.log 10044 Log file, useful mostly for debugging
Tune-18453-get.log 5408 Log file, useful mostly for debugging
Tune-18457-get.log 7975 Log file, useful mostly for debugging
Tune-18458-get.log 3318 Log file, useful mostly for debugging
These files should be available for 24 hours.