pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-18627-4786.ps) >>/Users/jc/w/tmp/Tune-18627-get.log 2>&1" returned status 256
http://thesession.org/tunes/4786

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-18627-4786.abc 358 ABC music file with the extracted tune(s)
Tune-18627-4786.ps 35052 PostScript
Tune-18627-4786.txt 358 Plain-text file with the extracted tune(s)
Tune-18627-get.log 3975 Log file, useful mostly for debugging
These files should be available for 24 hours.