pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-84108-1799_Skillern.ps) >>/Users/jc/w/tmp/Tune-84108-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/DftY/1799_Skillern.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-84108-1799_Skillern.abc 16955 ABC music file with the extracted tune(s)
Tune-84108-1799_Skillern.ps 128939 PostScript
Tune-84108-1799_Skillern.txt 16955 Plain-text file with the extracted tune(s)
Tune-84108-get.log 17179 Log file, useful mostly for debugging
These files should be available for 24 hours.