Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/cache/Tune-14342-301_MissMillarsStrathspey.abc/tmp"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4301-tmp.ps) >>/Users/jc/w/tmp/Tune-4301-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/cache/Tune-14342-301_MissMillarsStrathspey.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_43010.log 652851 Log file, useful mostly for debugging
Coll_43011.log 796132 Log file, useful mostly for debugging
Coll_43012.log 534620 Log file, useful mostly for debugging
Coll_43014.log 275010 Log file, useful mostly for debugging
Coll_43016.log 283409 Log file, useful mostly for debugging
Coll_43018.log 1447909 Log file, useful mostly for debugging
Coll_43019.log 750220 Log file, useful mostly for debugging
Form_43012.log 1721 Log file, useful mostly for debugging
Form_43014.log 232 Log file, useful mostly for debugging
Form_43019.log 912 Log file, useful mostly for debugging
Tune-4301-get.log 15111 Log file, useful mostly for debugging
Tune-4301-tmp.abc 178 ABC music file with the extracted tune(s)
Tune-4301-tmp.ps 6 PostScript
Tune-4301-tmp.txt 178 Plain-text file with the extracted tune(s)
Tune-43013-get.log 21082 Log file, useful mostly for debugging
Tune-43015-get.log 202112 Log file, useful mostly for debugging
Tune-43016-get.log 191428 Log file, useful mostly for debugging
Tune-43017-get.log 3858 Log file, useful mostly for debugging
These files should be available for 24 hours.