Got HTTP status 404 Not Found for "http://roaringjelly.org/~jc/music/book/Tunes/Straight_Skillern.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6833-Straight_Skillern.ps) >>/Users/jc/w/tmp/Tune-6833-get.log 2>&1" returned status 256
http://roaringjelly.org/~jc/music/book/Tunes/Straight_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
Sess-68339.log 102210 Log file, useful mostly for debugging
Tune-6833-Straight_Skillern.abc 155 ABC music file with the extracted tune(s)
Tune-6833-Straight_Skillern.ps 6 PostScript
Tune-6833-Straight_Skillern.txt 155 Plain-text file with the extracted tune(s)
Tune-6833-get.log 4217 Log file, useful mostly for debugging
Tune-68330-get.log 5924 Log file, useful mostly for debugging
Tune-68332-get.log 8740 Log file, useful mostly for debugging
Tune-68336-get.log 4863 Log file, useful mostly for debugging
Tune-68339-get.log 5921 Log file, useful mostly for debugging
These files should be available for 24 hours.