pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-98253-GraceSlashed.ps) >>/Users/jc/w/tmp/Tune-98253-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/abc/src/jcabc2ps-201511002/abc/GraceSlashed.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-98253-571_Turnpike_Bend.abc 326 ABC music file with the extracted tune(s)
Tune-98253-571_Turnpike_Bend.ps 36075 PostScript
Tune-98253-571_Turnpike_Bend.txt 326 Plain-text file with the extracted tune(s)
Tune-98253-GraceSlashed.abc 70 ABC music file with the extracted tune(s)
Tune-98253-GraceSlashed.ps 31145 PostScript
Tune-98253-GraceSlashed.txt 70 Plain-text file with the extracted tune(s)
Tune-98253-get.log 9025 Log file, useful mostly for debugging
These files should be available for 24 hours.