Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/Book27/Gow-CR-abc2.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-3932-Gow-CR-abc2.ps) >>/Users/jc/w/tmp/Tune-3932-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Book27/Gow-CR-abc2.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-3932-Gow-CR-abc2.abc 150 ABC music file with the extracted tune(s)
Tune-3932-Gow-CR-abc2.ps 6 PostScript
Tune-3932-Gow-CR-abc2.txt 150 Plain-text file with the extracted tune(s)
Tune-3932-get.log 8339 Log file, useful mostly for debugging
Tune-39320-get.log 4539 Log file, useful mostly for debugging
Tune-39321-get.log 7769 Log file, useful mostly for debugging
Tune-39323-get.log 4371 Log file, useful mostly for debugging
Tune-39324-get.log 5209 Log file, useful mostly for debugging
Tune-39325-get.log 3126 Log file, useful mostly for debugging
Tune-39326-get.log 4404 Log file, useful mostly for debugging
Tune-39329-get.log 9327 Log file, useful mostly for debugging
These files should be available for 24 hours.