Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/12Minuets12Dances/dance.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-8481-dance.ps) >>/Users/jc/w/tmp/Tune-8481-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/12Minuets12Dances/dance.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Coll_84811.log 457012 Log file, useful mostly for debugging
Tune-8481-dance.abc 155 ABC music file with the extracted tune(s)
Tune-8481-dance.ps 6 PostScript
Tune-8481-dance.txt 155 Plain-text file with the extracted tune(s)
Tune-8481-get.log 4033 Log file, useful mostly for debugging
Tune-84815-get.log 5754 Log file, useful mostly for debugging
Tune-84816-get.log 1404 Log file, useful mostly for debugging
Tune-84817-get.log 5761 Log file, useful mostly for debugging
These files should be available for 24 hours.