Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/1752/CDfNH1783.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-5767-CDfNH1783.ps) >>/Users/jc/w/tmp/Tune-5767-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/1752/CDfNH1783.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-5767-CDfNH1783.abc 146 ABC music file with the extracted tune(s)
Tune-5767-CDfNH1783.ps 6 PostScript
Tune-5767-CDfNH1783.txt 146 Plain-text file with the extracted tune(s)
Tune-5767-get.log 12226 Log file, useful mostly for debugging
Tune-57674-24CountryDances_1766_Johnson.abc 165 ABC music file with the extracted tune(s)
Tune-57674-24CountryDances_1766_Johnson.txt 165 Plain-text file with the extracted tune(s)
Tune-57674-get.log 16128 Log file, useful mostly for debugging
Tune-57676-get.log 6138 Log file, useful mostly for debugging
These files should be available for 24 hours.