Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/ONeills/Rare_Small/0059_Johnnies_Grey_Breeks.abc/book0"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6331-book0.ps) >>/Users/jc/w/tmp/Tune-6331-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/ONeills/Rare_Small/0059_Johnnies_Grey_Breeks.abc/book0

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.65 512x512 PNG]
filesizedescription
Tune-6331-book0.abc 182 ABC music file with the extracted tune(s)
Tune-6331-book0.ps 6 PostScript
Tune-6331-book0.txt 182 Plain-text file with the extracted tune(s)
Tune-6331-get.log 4155 Log file, useful mostly for debugging
Tune-63312-get.log 5958 Log file, useful mostly for debugging
Tune-63315-Top_and_Bottom-001.svg 14438 Scalable Vector Graphics format
Tune-63315-Top_and_Bottom.abc 431 ABC music file with the extracted tune(s)
Tune-63315-Top_and_Bottom.txt 431 Plain-text file with the extracted tune(s)
Tune-63315-get.log 10788 Log file, useful mostly for debugging
These files should be available for 24 hours.