pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-67856-Kerr_MM4-V1.ps) >>/Users/jc/w/tmp/Tune-67856-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Kerr/MM4/Kerr_MM4-V1.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
Tune-67856-Kerr_MM4-V1.abc 804 ABC music file with the extracted tune(s)
Tune-67856-Kerr_MM4-V1.ps 38661 PostScript
Tune-67856-Kerr_MM4-V1.txt 804 Plain-text file with the extracted tune(s)
Tune-67856-get.log 81828 Log file, useful mostly for debugging
These files should be available for 24 hours.