Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/DftY/Longman_Cotillons.abc/1770"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-11331-1770.ps) >>/Users/jc/w/tmp/Tune-11331-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/DftY/Longman_Cotillons.abc/1770

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_11331.log 452808 Log file, useful mostly for debugging
Tune-11331-1770.abc 159 ABC music file with the extracted tune(s)
Tune-11331-1770.ps 6 PostScript
Tune-11331-1770.txt 159 Plain-text file with the extracted tune(s)
Tune-11331-get.log 4017 Log file, useful mostly for debugging
These files should be available for 24 hours.