pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-89953-1781_Skillern.ps) >>/Users/jc/w/tmp/Tune-89953-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/DftY/1781_Skillern.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Tune-89953-1781_Skillern.abc 17775 ABC music file with the extracted tune(s)
Tune-89953-1781_Skillern.ps 130229 PostScript
Tune-89953-1781_Skillern.txt 17775 Plain-text file with the extracted tune(s)
Tune-89953-get.log 17081 Log file, useful mostly for debugging
These files should be available for 24 hours.