pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-95960-slip.ps) >>/Users/jc/w/tmp/Tune-95960-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/abc/mirror/perun.hscs.wmin.ac.uk/~jra/NMD/slip.txt

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-95960-get.log 8001 Log file, useful mostly for debugging
Tune-95960-slip.abc 335 ABC music file with the extracted tune(s)
Tune-95960-slip.ps 34017 PostScript
Tune-95960-slip.txt 335 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.