Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/SocialDances2002/Nelson.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-1255-Nelson.ps) >>/Users/jc/w/tmp/Tune-1255-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/SocialDances2002/Nelson.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-1255-Nelson.abc 155 ABC music file with the extracted tune(s)
Tune-1255-Nelson.ps 6 PostScript
Tune-1255-Nelson.txt 155 Plain-text file with the extracted tune(s)
Tune-1255-get.log 5406 Log file, useful mostly for debugging
Tune-12552-Round_Band_Book_of_Playford.abc 165 ABC music file with the extracted tune(s)
Tune-12552-Round_Band_Book_of_Playford.ps 6 PostScript
Tune-12552-Round_Band_Book_of_Playford.txt 165 Plain-text file with the extracted tune(s)
Tune-12552-get.log 4477 Log file, useful mostly for debugging
Tune-12557-GoldenBookOfFavoriteSongs1.abc 166 ABC music file with the extracted tune(s)
Tune-12557-GoldenBookOfFavoriteSongs1.txt 166 Plain-text file with the extracted tune(s)
Tune-12557-get.log 3492 Log file, useful mostly for debugging
These files should be available for 24 hours.