Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1784/Kerr_MM3-V2.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-24611-Kerr_MM3-V2.ps) >>/Users/jc/w/tmp/Tune-24611-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1784/Kerr_MM3-V2.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-24611-Kerr_MM3-V2.abc 148 ABC music file with the extracted tune(s)
Tune-24611-Kerr_MM3-V2.ps 6 PostScript
Tune-24611-Kerr_MM3-V2.txt 148 Plain-text file with the extracted tune(s)
Tune-24611-Montgomeries_Hornpipe_D.abc 548 ABC music file with the extracted tune(s)
Tune-24611-Montgomeries_Hornpipe_D.gif 0 Graphics Interchange Format, the proprietary scan-line picture format
Tune-24611-Montgomeries_Hornpipe_D.ps 35199 PostScript
Tune-24611-Montgomeries_Hornpipe_D.txt 548 Plain-text file with the extracted tune(s)
Tune-24611-get.log 9653 Log file, useful mostly for debugging
These files should be available for 24 hours.