pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-18847-Rocky_Moorland-Gm-16-4.ps) >>/Users/jc/w/tmp/Tune-18847-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/ONeills/march/Rocky_Moorland-Gm-16-4.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Coll_18847.log 1164111 Log file, useful mostly for debugging
Tune-18847-Rocky_Moorland-Gm-16-4.abc 532 ABC music file with the extracted tune(s)
Tune-18847-Rocky_Moorland-Gm-16-4.ps 34741 PostScript
Tune-18847-Rocky_Moorland-Gm-16-4.txt 532 Plain-text file with the extracted tune(s)
Tune-18847-get.log 5363 Log file, useful mostly for debugging
These files should be available for 24 hours.