pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6886-1799_Skillern.ps) >>/Users/jc/w/tmp/Tune-6886-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
Coll_68861.log 1327910 Log file, useful mostly for debugging
Coll_68863.log 667898 Log file, useful mostly for debugging
Coll_68864.log 288545 Log file, useful mostly for debugging
Coll_68867.log 574281 Log file, useful mostly for debugging
Tune-6886-1799_Skillern.abc 16955 ABC music file with the extracted tune(s)
Tune-6886-1799_Skillern.ps 128938 PostScript
Tune-6886-1799_Skillern.txt 16955 Plain-text file with the extracted tune(s)
Tune-6886-get.log 17162 Log file, useful mostly for debugging
Tune-68860-get.log 4791 Log file, useful mostly for debugging
Tune-68867-get.log 6561 Log file, useful mostly for debugging
Tune-68868-get.log 5060 Log file, useful mostly for debugging
These files should be available for 24 hours.