Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/1784/ERM-V1.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-8686-ERM-V1.ps) >>/Users/jc/w/tmp/Tune-8686-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/1784/ERM-V1.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_86862.log 946 Log file, useful mostly for debugging
Form_86868.log 1689 Log file, useful mostly for debugging
Tune-8686-ERM-V1.abc 143 ABC music file with the extracted tune(s)
Tune-8686-ERM-V1.ps 6 PostScript
Tune-8686-ERM-V1.txt 143 Plain-text file with the extracted tune(s)
Tune-8686-get.log 3978 Log file, useful mostly for debugging
Tune-86862-get.log 5757 Log file, useful mostly for debugging
These files should be available for 24 hours.