pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6780-slip.ps) >>/Users/jc/w/tmp/Tune-6780-get.log 2>&1" returned status 256
http://www.andyhornby.net/Music/slip jigs.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-6780-get.log 25273 Log file, useful mostly for debugging
Tune-6780-slip.abc 379 ABC music file with the extracted tune(s)
Tune-6780-slip.ps 33521 PostScript
Tune-6780-slip.txt 379 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.