Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/_/CDSS_Gems.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7923-CDSS_Gems.ps) >>/Users/jc/w/tmp/Tune-7923-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/_/CDSS_Gems.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_79235.log 857207 Log file, useful mostly for debugging
Coll_79237.log 264664 Log file, useful mostly for debugging
Tune-7923-CDSS_Gems.abc 143 ABC music file with the extracted tune(s)
Tune-7923-CDSS_Gems.ps 6 PostScript
Tune-7923-CDSS_Gems.txt 143 Plain-text file with the extracted tune(s)
Tune-7923-get.log 4025 Log file, useful mostly for debugging
Tune-79238-get.log 1473 Log file, useful mostly for debugging
Tune-79239-get.log 5624 Log file, useful mostly for debugging
These files should be available for 24 hours.