pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-20518-20641_Allegretto.ps) >>/Users/jc/w/tmp/Tune-20518-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/MoF/20641_Allegretto.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-20518-20641_Allegretto.abc 1204 ABC music file with the extracted tune(s)
Tune-20518-20641_Allegretto.ps 43629 PostScript
Tune-20518-20641_Allegretto.txt 1204 Plain-text file with the extracted tune(s)
Tune-20518-2231_the_Cossy_Jigg.abc 1108 ABC music file with the extracted tune(s)
Tune-20518-2231_the_Cossy_Jigg.gif 0 Graphics Interchange Format, the proprietary scan-line picture format
Tune-20518-2231_the_Cossy_Jigg.ps 41537 PostScript
Tune-20518-2231_the_Cossy_Jigg.txt 1108 Plain-text file with the extracted tune(s)
Tune-20518-get.log 25270 Log file, useful mostly for debugging
These files should be available for 24 hours.