Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/abc/session/RoM/R-001.abc/set"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-20540-set.ps) >>/Users/jc/w/tmp/Tune-20540-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/abc/session/RoM/R-001.abc/set

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_20540.log 259041 Log file, useful mostly for debugging
Tune-20540-get.log 3964 Log file, useful mostly for debugging
Tune-20540-set.abc 152 ABC music file with the extracted tune(s)
Tune-20540-set.ps 6 PostScript
Tune-20540-set.txt 152 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.