Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/1766/LondonMagazine.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-1917-LondonMagazine.ps) >>/Users/jc/w/tmp/Tune-1917-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/1766/LondonMagazine.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-1917-LondonMagazine.abc 151 ABC music file with the extracted tune(s)
Tune-1917-LondonMagazine.ps 6 PostScript
Tune-1917-LondonMagazine.txt 151 Plain-text file with the extracted tune(s)
Tune-1917-get.log 4150 Log file, useful mostly for debugging
Tune-19170-MollPeatlyNewWay_PLFD1665_186-001.svg 14252 Scalable Vector Graphics format
Tune-19170-MollPeatlyNewWay_PLFD1665_186.abc 459 ABC music file with the extracted tune(s)
Tune-19170-MollPeatlyNewWay_PLFD1665_186.txt 459 Plain-text file with the extracted tune(s)
Tune-19170-get.log 5233 Log file, useful mostly for debugging
Tune-19177-get.log 4595 Log file, useful mostly for debugging
These files should be available for 24 hours.