pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-20962-1780_Thompson.ps) >>/Users/jc/w/tmp/Tune-20962-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/dfty/1780_Thompson.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_20962.log 132485 Log file, useful mostly for debugging
Tune-20962-1780_Thompson.abc 20869 ABC music file with the extracted tune(s)
Tune-20962-1780_Thompson.ps 120677 PostScript
Tune-20962-1780_Thompson.txt 20869 Plain-text file with the extracted tune(s)
Tune-20962-get.log 18798 Log file, useful mostly for debugging
These files should be available for 24 hours.