Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/Book18/book_of_rights.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7087-book_of_rights.ps) >>/Users/jc/w/tmp/Tune-7087-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Book18/book_of_rights.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Tune-7087-book_of_rights.abc 153 ABC music file with the extracted tune(s)
Tune-7087-book_of_rights.ps 6 PostScript
Tune-7087-book_of_rights.txt 153 Plain-text file with the extracted tune(s)
Tune-7087-get.log 4162 Log file, useful mostly for debugging
Tune-70871-get.log 4392 Log file, useful mostly for debugging
Tune-70873-get.log 5242 Log file, useful mostly for debugging
Tune-70874-get.log 4895 Log file, useful mostly for debugging
Tune-70875-get.log 11594 Log file, useful mostly for debugging
Tune-70876-get.log 1478 Log file, useful mostly for debugging
Tune-70877-get.log 4245 Log file, useful mostly for debugging
Tune-70878-get.log 4434 Log file, useful mostly for debugging
These files should be available for 24 hours.