Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/GM/Marine_Joke.abc/1750"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7654-1750.ps) >>/Users/jc/w/tmp/Tune-7654-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/GM/Marine_Joke.abc/1750

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_76543.log 260446 Log file, useful mostly for debugging
Coll_76549.log 266066 Log file, useful mostly for debugging
Tune-7654-1750.abc 151 ABC music file with the extracted tune(s)
Tune-7654-1750.ps 6 PostScript
Tune-7654-1750.txt 151 Plain-text file with the extracted tune(s)
Tune-7654-get.log 3956 Log file, useful mostly for debugging
Tune-76541-get.log 5069 Log file, useful mostly for debugging
Tune-76542-get.log 4841 Log file, useful mostly for debugging
Tune-76543-get.log 6318 Log file, useful mostly for debugging
Tune-76545-get.log 7270 Log file, useful mostly for debugging
These files should be available for 24 hours.