Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/Kerr_MM/Kohlers1.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-1144-Kohlers1.ps) >>/Users/jc/w/tmp/Tune-1144-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/Kerr_MM/Kohlers1.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Coll_1144.log 1182830 Log file, useful mostly for debugging
Coll_11443.log 282925 Log file, useful mostly for debugging
Coll_11446.log 273090 Log file, useful mostly for debugging
Tune-1144-Kohlers1.abc 148 ABC music file with the extracted tune(s)
Tune-1144-Kohlers1.ps 6 PostScript
Tune-1144-Kohlers1.txt 148 Plain-text file with the extracted tune(s)
Tune-1144-get.log 4042 Log file, useful mostly for debugging
Tune-11442-get.log 1561 Log file, useful mostly for debugging
These files should be available for 24 hours.