Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/cache/Tune-24541-waltz.abc/tmp"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4469-tmp.ps) >>/Users/jc/w/tmp/Tune-4469-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/cache/Tune-24541-waltz.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_44690.log 466810 Log file, useful mostly for debugging
Coll_44691.log 445809 Log file, useful mostly for debugging
Coll_44693.log 636216 Log file, useful mostly for debugging
Coll_44695.log 473809 Log file, useful mostly for debugging
Coll_44696.log 598293 Log file, useful mostly for debugging
Coll_44697.log 283409 Log file, useful mostly for debugging
Form_44690.log 897 Log file, useful mostly for debugging
Tune-4469-get.log 7961 Log file, useful mostly for debugging
Tune-4469-tmp.abc 158 ABC music file with the extracted tune(s)
Tune-4469-tmp.ps 6 PostScript
Tune-4469-tmp.txt 158 Plain-text file with the extracted tune(s)
Tune-44690-get.log 6240 Log file, useful mostly for debugging
Tune-44692-get.log 178983 Log file, useful mostly for debugging
Tune-44694-get.log 11288 Log file, useful mostly for debugging
Tune-44695-get.log 11744 Log file, useful mostly for debugging
Tune-44696-get.log 181201 Log file, useful mostly for debugging
Tune-44697-get.log 10008 Log file, useful mostly for debugging
Tune-44698-get.log 14169 Log file, useful mostly for debugging
Tune-44699-get.log 4230 Log file, useful mostly for debugging
These files should be available for 24 hours.