pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-91799-1793_Preston.ps) >>/Users/jc/w/tmp/Tune-91799-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/dfty/1793_Preston.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-91799-1793_Preston.abc 21686 ABC music file with the extracted tune(s)
Tune-91799-1793_Preston.ps 135035 PostScript
Tune-91799-1793_Preston.txt 21686 Plain-text file with the extracted tune(s)
Tune-91799-get.log 30106 Log file, useful mostly for debugging
These files should be available for 24 hours.