pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-18710-7499.ps) >>/Users/jc/w/tmp/Tune-18710-get.log 2>&1" returned status 256
http://thesession.org/tunes/7499

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-18710-7499.abc 252 ABC music file with the extracted tune(s)
Tune-18710-7499.ps 35007 PostScript
Tune-18710-7499.txt 252 Plain-text file with the extracted tune(s)
Tune-18710-get.log 8684 Log file, useful mostly for debugging
These files should be available for 24 hours.