pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-16291-8946.ps) >>/Users/jc/w/tmp/Tune-16291-get.log 2>&1" returned status 256
http://thesession.org/tunes/8946

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-16291-8946.abc 247 ABC music file with the extracted tune(s)
Tune-16291-8946.ps 35997 PostScript
Tune-16291-8946.txt 247 Plain-text file with the extracted tune(s)
Tune-16291-get.log 3969 Log file, useful mostly for debugging
These files should be available for 24 hours.