pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-5654-20180912-Colin_Hume_tunes.ps) >>/Users/jc/w/tmp/Tune-5654-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/abc/mirror/Colin_Hume/20180912-Colin_Hume_tunes.abc

Error exit status 256; here are some files to check:
[P=get.cgi V=1/1 B=0 scale=0.60 512x512 PNG]
filesizedescription
Coll_56547.log 236004 Log file, useful mostly for debugging
Find_5654.log 2836 Log file, useful mostly for debugging
Form_56547.log 2547 Log file, useful mostly for debugging
Tune-5654-20180912-Colin_Hume_tunes.abc 422 ABC music file with the extracted tune(s)
Tune-5654-20180912-Colin_Hume_tunes.ps 34672 PostScript
Tune-5654-20180912-Colin_Hume_tunes.txt 422 Plain-text file with the extracted tune(s)
Tune-5654-get.log 4698 Log file, useful mostly for debugging
Tune-56540-get.log 3161 Log file, useful mostly for debugging
Tune-56541-get.log 4064 Log file, useful mostly for debugging
Tune-56546-get.log 3253 Log file, useful mostly for debugging
These files should be available for 24 hours.