pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-83758-allans.ps) >>/Users/jc/w/tmp/Tune-83758-get.log 2>&1" returned status 256
http://montrealsession.cechire.com/assets/abc/allans.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-83758-allans.abc 732 ABC music file with the extracted tune(s)
Tune-83758-allans.ps 39130 PostScript
Tune-83758-allans.txt 732 Plain-text file with the extracted tune(s)
Tune-83758-get.log 4207 Log file, useful mostly for debugging
These files should be available for 24 hours.