Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1780/AMHSI-abc1.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-3844-AMHSI-abc1.ps) >>/Users/jc/w/tmp/Tune-3844-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1780/AMHSI-abc1.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-3844-AMHSI-abc1.abc 147 ABC music file with the extracted tune(s)
Tune-3844-AMHSI-abc1.ps 6 PostScript
Tune-3844-AMHSI-abc1.txt 147 Plain-text file with the extracted tune(s)
Tune-3844-get.log 4064 Log file, useful mostly for debugging
Tune-38442-get.log 4111 Log file, useful mostly for debugging
Tune-38446-JohnFrench.abc 147 ABC music file with the extracted tune(s)
Tune-38446-JohnFrench.pdf 2217 Portable Data Format
Tune-38446-JohnFrench.ps 6 PostScript
Tune-38446-JohnFrench.txt 147 Plain-text file with the extracted tune(s)
Tune-38446-get.log 4886 Log file, useful mostly for debugging
Tune-38448-get.log 3150 Log file, useful mostly for debugging
Tune-38449-get.log 4014 Log file, useful mostly for debugging
These files should be available for 24 hours.