Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/session/NYE/reel/Petronella_set-D,G,A,Em-32-3.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-79209-Petronella_set-D,G,A,Em-32-3.ps) >>/Users/jc/w/tmp/Tune-79209-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/session/NYE/reel/Petronella_set-D,G,A,Em-32-3.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-79209-Petronella_set-D,G,A,Em-32-3.abc 172 ABC music file with the extracted tune(s)
Tune-79209-Petronella_set-D,G,A,Em-32-3.ps 6 PostScript
Tune-79209-Petronella_set-D,G,A,Em-32-3.txt 172 Plain-text file with the extracted tune(s)
Tune-79209-get.log 9727 Log file, useful mostly for debugging
These files should be available for 24 hours.