Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1791/MSRPB.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6460-MSRPB.ps) >>/Users/jc/w/tmp/Tune-6460-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1791/MSRPB.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_64606.log 136353 Log file, useful mostly for debugging
Form_64604.log 826 Log file, useful mostly for debugging
Tune-6460-MSRPB.abc 142 ABC music file with the extracted tune(s)
Tune-6460-MSRPB.ps 6 PostScript
Tune-6460-MSRPB.txt 142 Plain-text file with the extracted tune(s)
Tune-6460-get.log 3961 Log file, useful mostly for debugging
Tune-64600-get.log 7839 Log file, useful mostly for debugging
Tune-64601-Button_Whitaker_SelectionOfDancesReelsAndWaltzes_1.abc 187 ABC music file with the extracted tune(s)
Tune-64601-Button_Whitaker_SelectionOfDancesReelsAndWaltzes_1.txt 187 Plain-text file with the extracted tune(s)
Tune-64601-get.log 3902 Log file, useful mostly for debugging
Tune-64602-get.log 23416 Log file, useful mostly for debugging
Tune-64606-get.log 4224 Log file, useful mostly for debugging
These files should be available for 24 hours.