Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/session/Oivan_Ilo/Talgoxen-G-32-2.abc/shottish"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-15180-shottish.ps) >>/Users/jc/w/tmp/Tune-15180-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/session/Oivan_Ilo/Talgoxen-G-32-2.abc/shottish

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_15180.log 914017 Log file, useful mostly for debugging
Tune-15180-get.log 4139 Log file, useful mostly for debugging
Tune-15180-shottish.abc 169 ABC music file with the extracted tune(s)
Tune-15180-shottish.ps 6 PostScript
Tune-15180-shottish.txt 169 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.