Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1796/CMCIT.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4287-CMCIT.ps) >>/Users/jc/w/tmp/Tune-4287-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1796/CMCIT.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-4287-CMCIT.abc 142 ABC music file with the extracted tune(s)
Tune-4287-CMCIT.ps 6 PostScript
Tune-4287-CMCIT.txt 142 Plain-text file with the extracted tune(s)
Tune-4287-get.log 3959 Log file, useful mostly for debugging
Tune-42872-get.log 5634 Log file, useful mostly for debugging
Tune-42873-get.log 5389 Log file, useful mostly for debugging
Tune-42874-get.log 8900 Log file, useful mostly for debugging
Tune-42875-get.log 9440 Log file, useful mostly for debugging
Tune-42879-get.log 4753 Log file, useful mostly for debugging
These files should be available for 24 hours.