X:13 not found in http://www.village-music-project.org.uk/abc/gibbon.abc
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-29027-gibbon.ps) >>/Users/jc/w/tmp/Tune-29027-get.log 2>&1" returned status 256
http://www.village-music-project.org.uk/abc/gibbon.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-29027-get.log 4226 Log file, useful mostly for debugging
Tune-29027-gibbon.abc 0 ABC music file with the extracted tune(s)
Tune-29027-gibbon.ps 6 PostScript
Tune-29027-gibbon.txt 0 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.