pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7836-ShoeTheDonkey.ps) >>/Users/jc/w/tmp/Tune-7836-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/abc/contrib/Tunes/ShoeTheDonkey.abc

Error exit status 256; here are some files to check:
[P=get.cgi V=1/1 B=0 scale=0.60 512x512 PNG]
filesizedescription
Form_78360.log 863 Log file, useful mostly for debugging
Form_78365.log 851 Log file, useful mostly for debugging
Tune-7836-ShoeTheDonkey.abc 421 ABC music file with the extracted tune(s)
Tune-7836-ShoeTheDonkey.ps 33947 PostScript
Tune-7836-ShoeTheDonkey.txt 421 Plain-text file with the extracted tune(s)
Tune-7836-get.log 5378 Log file, useful mostly for debugging
Tune-78360-get.log 1605 Log file, useful mostly for debugging
Tune-78361-get.log 2935 Log file, useful mostly for debugging
Tune-78362-get.log 4146 Log file, useful mostly for debugging
Tune-78364-get.log 3459 Log file, useful mostly for debugging
Tune-78365-get.log 8185 Log file, useful mostly for debugging
Tune-78367-get.log 7226 Log file, useful mostly for debugging
Tune-78367-r.abc 801 ABC music file with the extracted tune(s)
Tune-78367-r.txt 801 Plain-text file with the extracted tune(s)
Tune-78368-Grand_Chaine_.abc 281 ABC music file with the extracted tune(s)
Tune-78368-Grand_Chaine_.gif 0 Graphics Interchange Format, the proprietary scan-line picture format
Tune-78368-Grand_Chaine_.ps 34843 PostScript
Tune-78368-Grand_Chaine_.txt 281 Plain-text file with the extracted tune(s)
Tune-78368-get.log 5012 Log file, useful mostly for debugging
These files should be available for 24 hours.