pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-93255-5016.ps) >>/Users/jc/w/tmp/Tune-93255-get.log 2>&1" returned status 256
http://thesession.org/tunes/5016

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-93255-5016.abc 644 ABC music file with the extracted tune(s)
Tune-93255-5016.ps 20476 PostScript
Tune-93255-5016.txt 644 Plain-text file with the extracted tune(s)
Tune-93255-get.log 10576 Log file, useful mostly for debugging
These files should be available for 24 hours.