Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/cache/Tune-23411-reel.abc/tmp"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-1488-tmp.ps) >>/Users/jc/w/tmp/Tune-1488-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/cache/Tune-23411-reel.abc/tmp

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_14881.log 1327510 Log file, useful mostly for debugging
Coll_14886.log 275009 Log file, useful mostly for debugging
Find_14886.log 1381 Log file, useful mostly for debugging
Form_14889.log 1079 Log file, useful mostly for debugging
Tune-1488-get.log 3971 Log file, useful mostly for debugging
Tune-1488-tmp.abc 157 ABC music file with the extracted tune(s)
Tune-1488-tmp.ps 6 PostScript
Tune-1488-tmp.txt 157 Plain-text file with the extracted tune(s)
Tune-14885-get.log 4564 Log file, useful mostly for debugging
Tune-14886-get.log 3583 Log file, useful mostly for debugging
These files should be available for 24 hours.