Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/JamesOswald/CPC/v12.abc/proto"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6666-proto.ps) >>/Users/jc/w/tmp/Tune-6666-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/JamesOswald/CPC/v12.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_66660.log 264661 Log file, useful mostly for debugging
Coll_66662.log 264661 Log file, useful mostly for debugging
Coll_66664.log 228353 Log file, useful mostly for debugging
Coll_66666.log 492271 Log file, useful mostly for debugging
Coll_66669.log 663626 Log file, useful mostly for debugging
Form_6666.log 1685 Log file, useful mostly for debugging
Form_66660.log 872 Log file, useful mostly for debugging
Form_66664.log 970 Log file, useful mostly for debugging
Form_66666.log 825 Log file, useful mostly for debugging
Tune-6666-get.log 4005 Log file, useful mostly for debugging
Tune-6666-proto.abc 157 ABC music file with the extracted tune(s)
Tune-6666-proto.ps 6 PostScript
Tune-6666-proto.txt 157 Plain-text file with the extracted tune(s)
Tune-66661-get.log 9217 Log file, useful mostly for debugging
Tune-66665-get.log 1400 Log file, useful mostly for debugging
Tune-66667-get.log 3870 Log file, useful mostly for debugging
These files should be available for 24 hours.