pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-17688-MarketLass.ps) >>/Users/jc/w/tmp/Tune-17688-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/england/MarketLass.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_17688.log 284330 Log file, useful mostly for debugging
Tune-17688-MarketLass.abc 2166 ABC music file with the extracted tune(s)
Tune-17688-MarketLass.ps 52792 PostScript
Tune-17688-MarketLass.txt 2166 Plain-text file with the extracted tune(s)
Tune-17688-get.log 5771 Log file, useful mostly for debugging
These files should be available for 24 hours.