pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-56680-gf.ps) >>/Users/jc/w/tmp/Tune-56680-get.log 2>&1" returned status 256
http://sessionite.com/docs/gf.abc

Error exit status 256; here are some files to check:
[P=get.cgi V=1/1 B=0 scale=0.60 512x512 PNG]
filesizedescription
Tune-56680-get.log 69416 Log file, useful mostly for debugging
Tune-56680-gf.abc 468 ABC music file with the extracted tune(s)
Tune-56680-gf.ps 37970 PostScript
Tune-56680-gf.txt 468 Plain-text file with the extracted tune(s)
These files should be available for 24 hours.