pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-51793-CHEVCHS3.ps) >>/Users/jc/w/tmp/Tune-51793-get.log 2>&1" returned status 256
http://www.gulfweb.net/rlwalker/abc/CHEVCHS3.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-51793-CHEVCHS3.abc 149 ABC music file with the extracted tune(s)
Tune-51793-CHEVCHS3.ps 32231 PostScript
Tune-51793-CHEVCHS3.txt 149 Plain-text file with the extracted tune(s)
Tune-51793-get.log 4171 Log file, useful mostly for debugging
These files should be available for 24 hours.