Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1800/AbrahamMackintosh.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-9154-AbrahamMackintosh.ps) >>/Users/jc/w/tmp/Tune-9154-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1800/AbrahamMackintosh.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_91545.log 2297350 Log file, useful mostly for debugging
Tune-9154-AbrahamMackintosh.abc 154 ABC music file with the extracted tune(s)
Tune-9154-AbrahamMackintosh.ps 6 PostScript
Tune-9154-AbrahamMackintosh.txt 154 Plain-text file with the extracted tune(s)
Tune-9154-get.log 4211 Log file, useful mostly for debugging
Tune-91540-get.log 5430 Log file, useful mostly for debugging
Tune-91541-get.log 10684 Log file, useful mostly for debugging
Tune-91543-dim.abc 140 ABC music file with the extracted tune(s)
Tune-91543-dim.ps 6 PostScript
Tune-91543-dim.txt 140 Plain-text file with the extracted tune(s)
Tune-91543-get.log 3846 Log file, useful mostly for debugging
Tune-91548-get.log 10739 Log file, useful mostly for debugging
These files should be available for 24 hours.