Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/JamesOswald/CPC/test.abc/proto"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6010-proto.ps) >>/Users/jc/w/tmp/Tune-6010-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/JamesOswald/CPC/test.abc/proto

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_60104.log 529322 Log file, useful mostly for debugging
Form_60105.log 978 Log file, useful mostly for debugging
Tune-6010-get.log 4009 Log file, useful mostly for debugging
Tune-6010-proto.abc 158 ABC music file with the extracted tune(s)
Tune-6010-proto.ps 6 PostScript
Tune-6010-proto.txt 158 Plain-text file with the extracted tune(s)
Tune-60101-get.log 4895 Log file, useful mostly for debugging
Tune-60102-get.log 1388 Log file, useful mostly for debugging
Tune-60106-get.log 1388 Log file, useful mostly for debugging
Tune-60107-1753.abc 153 ABC music file with the extracted tune(s)
Tune-60107-1753.ps 6 PostScript
Tune-60107-1753.txt 153 Plain-text file with the extracted tune(s)
Tune-60107-get.log 4012 Log file, useful mostly for debugging
These files should be available for 24 hours.