pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-67447-21421.ps) >>/Users/jc/w/tmp/Tune-67447-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/ERM/21421=Barcarole_from_Masaniello-V2.abc

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Tune-67447-21421.abc 1194 ABC music file with the extracted tune(s)
Tune-67447-21421.ps 43722 PostScript
Tune-67447-21421.txt 1194 Plain-text file with the extracted tune(s)
Tune-67447-get.log 4780 Log file, useful mostly for debugging
These files should be available for 24 hours.