Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/cache/Tune-15523-24CountryDances_1799_Preston.abc/tmp"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4173-tmp.ps) >>/Users/jc/w/tmp/Tune-4173-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/cache/Tune-15523-24CountryDances_1799_Preston.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_41732.log 462611 Log file, useful mostly for debugging
Coll_41735.log 276410 Log file, useful mostly for debugging
Coll_41736.log 270810 Log file, useful mostly for debugging
Coll_41738.log 547219 Log file, useful mostly for debugging
Coll_41739.log 282011 Log file, useful mostly for debugging
Form_4173.log 832 Log file, useful mostly for debugging
Form_41733.log 987 Log file, useful mostly for debugging
Form_41734.log 978 Log file, useful mostly for debugging
Form_41735.log 855 Log file, useful mostly for debugging
Tune-4173-get.log 48402 Log file, useful mostly for debugging
Tune-4173-tmp.abc 181 ABC music file with the extracted tune(s)
Tune-4173-tmp.ps 6 PostScript
Tune-4173-tmp.txt 181 Plain-text file with the extracted tune(s)
Tune-41731-get.log 4987 Log file, useful mostly for debugging
Tune-41733-get.log 2868 Log file, useful mostly for debugging
Tune-41734-get.log 8872 Log file, useful mostly for debugging
Tune-41736-get.log 6102 Log file, useful mostly for debugging
Tune-41737-get.log 180205 Log file, useful mostly for debugging
Tune-41738-get.log 5078 Log file, useful mostly for debugging
Tune-41739-get.log 8723 Log file, useful mostly for debugging
These files should be available for 24 hours.