Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/slide/Gow-CSR4-abc2.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-5502-Gow-CSR4-abc2.ps) >>/Users/jc/w/tmp/Tune-5502-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/slide/Gow-CSR4-abc2.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Coll_55020.log 922421 Log file, useful mostly for debugging
Coll_55025.log 265210 Log file, useful mostly for debugging
Coll_55026.log 476608 Log file, useful mostly for debugging
Tune-5502-Gow-CSR4-abc2.abc 151 ABC music file with the extracted tune(s)
Tune-5502-Gow-CSR4-abc2.ps 6 PostScript
Tune-5502-Gow-CSR4-abc2.txt 151 Plain-text file with the extracted tune(s)
Tune-5502-get.log 4135 Log file, useful mostly for debugging
Tune-55021-get.log 4045 Log file, useful mostly for debugging
Tune-55022-get.log 169917 Log file, useful mostly for debugging
Tune-55023-get.log 183582 Log file, useful mostly for debugging
Tune-55025-get.log 11842 Log file, useful mostly for debugging
Tune-55028-get.log 20957 Log file, useful mostly for debugging
These files should be available for 24 hours.