Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/_/ThomasMarsden.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-1724-ThomasMarsden.ps) >>/Users/jc/w/tmp/Tune-1724-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/_/ThomasMarsden.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_17240.log 285735 Log file, useful mostly for debugging
Coll_17244.log 651651 Log file, useful mostly for debugging
Coll_17249.log 282925 Log file, useful mostly for debugging
Tune-1724-ThomasMarsden.abc 147 ABC music file with the extracted tune(s)
Tune-1724-ThomasMarsden.ps 6 PostScript
Tune-1724-ThomasMarsden.txt 147 Plain-text file with the extracted tune(s)
Tune-1724-get.log 4111 Log file, useful mostly for debugging
Tune-17247-get.log 5965 Log file, useful mostly for debugging
Tune-17248-get.log 6140 Log file, useful mostly for debugging
These files should be available for 24 hours.