Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/ERM/cont.abc/save"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-81019-save.ps) >>/Users/jc/w/tmp/Tune-81019-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/ERM/cont.abc/save

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_81019.log 448609 Log file, useful mostly for debugging
Tune-81019-get.log 3935 Log file, useful mostly for debugging
Tune-81019-save.abc 145 ABC music file with the extracted tune(s)
Tune-81019-save.ps 6 PostScript
Tune-81019-save.txt 145 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.