pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-65787-4120_Rover.ps) >>/Users/jc/w/tmp/Tune-65787-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/Kerr/MM4/4120_Rover.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-65787-4120_Rover.abc 404 ABC music file with the extracted tune(s)
Tune-65787-4120_Rover.ps 33938 PostScript
Tune-65787-4120_Rover.txt 404 Plain-text file with the extracted tune(s)
Tune-65787-get.log 4417 Log file, useful mostly for debugging
These files should be available for 24 hours.