Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1804/Urbani_Liston_1800.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-6330-Urbani_Liston_1800.ps) >>/Users/jc/w/tmp/Tune-6330-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1804/Urbani_Liston_1800.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Tune-6330-Urbani_Liston_1800.abc 155 ABC music file with the extracted tune(s)
Tune-6330-Urbani_Liston_1800.ps 6 PostScript
Tune-6330-Urbani_Liston_1800.txt 155 Plain-text file with the extracted tune(s)
Tune-6330-get.log 4236 Log file, useful mostly for debugging
Tune-63304-RobertPurdie_TomThumb.abc 158 ABC music file with the extracted tune(s)
Tune-63304-RobertPurdie_TomThumb.pdf 2217 Portable Data Format
Tune-63304-RobertPurdie_TomThumb.ps 6 PostScript
Tune-63304-RobertPurdie_TomThumb.txt 158 Plain-text file with the extracted tune(s)
Tune-63304-get.log 5203 Log file, useful mostly for debugging
These files should be available for 24 hours.