Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/JamesOswald/CPC/21090_.abc/all"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-8096-all.ps) >>/Users/jc/w/tmp/Tune-8096-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/JamesOswald/CPC/21090_.abc/all

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_80969.log 462766 Log file, useful mostly for debugging
Form_8096.log 1113 Log file, useful mostly for debugging
Form_80967.log 827 Log file, useful mostly for debugging
Tune-8096-21532_LENA_2-001.svg 28879 Scalable Vector Graphics format
Tune-8096-21532_LENA_2.abc 796 ABC music file with the extracted tune(s)
Tune-8096-21532_LENA_2.txt 796 Plain-text file with the extracted tune(s)
Tune-8096-all.abc 158 ABC music file with the extracted tune(s)
Tune-8096-all.ps 6 PostScript
Tune-8096-all.txt 158 Plain-text file with the extracted tune(s)
Tune-8096-get.log 8041 Log file, useful mostly for debugging
Tune-80963-get.log 4216 Log file, useful mostly for debugging
Tune-80964-get.log 5913 Log file, useful mostly for debugging
These files should be available for 24 hours.