Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/Book45/Kohlers2.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-9646-Kohlers2.ps) >>/Users/jc/w/tmp/Tune-9646-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Book45/Kohlers2.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Tune-9646-Kohlers2.abc 147 ABC music file with the extracted tune(s)
Tune-9646-Kohlers2.ps 6 PostScript
Tune-9646-Kohlers2.txt 147 Plain-text file with the extracted tune(s)
Tune-9646-get.log 4034 Log file, useful mostly for debugging
Tune-96463-24CountryDances_1809_Cahusac_JC.abc 184 ABC music file with the extracted tune(s)
Tune-96463-24CountryDances_1809_Cahusac_JC.txt 184 Plain-text file with the extracted tune(s)
Tune-96463-get.log 7627 Log file, useful mostly for debugging
Tune-96466-24CountryDances_1818_Button_Whitaker.abc 173 ABC music file with the extracted tune(s)
Tune-96466-24CountryDances_1818_Button_Whitaker.txt 173 Plain-text file with the extracted tune(s)
Tune-96466-get.log 3654 Log file, useful mostly for debugging
These files should be available for 24 hours.