Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/jpg/AMHSI-abc1.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-4256-AMHSI-abc1.ps) >>/Users/jc/w/tmp/Tune-4256-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/jpg/AMHSI-abc1.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Form_42563.log 817 Log file, useful mostly for debugging
Form_42569.log 1200 Log file, useful mostly for debugging
Tune-4256-AMHSI-abc1.abc 146 ABC music file with the extracted tune(s)
Tune-4256-AMHSI-abc1.ps 6 PostScript
Tune-4256-AMHSI-abc1.txt 146 Plain-text file with the extracted tune(s)
Tune-4256-get.log 4056 Log file, useful mostly for debugging
Tune-42561-24CountryDances_1808_Goulding.abc 166 ABC music file with the extracted tune(s)
Tune-42561-24CountryDances_1808_Goulding.ps 6 PostScript
Tune-42561-24CountryDances_1808_Goulding.txt 166 Plain-text file with the extracted tune(s)
Tune-42561-get.log 4511 Log file, useful mostly for debugging
These files should be available for 24 hours.