Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1813/BB50.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-3056-BB50.ps) >>/Users/jc/w/tmp/Tune-3056-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1813/BB50.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-3056-BB50.abc 141 ABC music file with the extracted tune(s)
Tune-3056-BB50.ps 6 PostScript
Tune-3056-BB50.txt 141 Plain-text file with the extracted tune(s)
Tune-3056-get.log 3938 Log file, useful mostly for debugging
Tune-30560-24CountryDances_1762_Thompson.abc 165 ABC music file with the extracted tune(s)
Tune-30560-24CountryDances_1762_Thompson.ps 6 PostScript
Tune-30560-24CountryDances_1762_Thompson.txt 165 Plain-text file with the extracted tune(s)
Tune-30560-get.log 4505 Log file, useful mostly for debugging
Tune-30569-Wilson_Harmony_4NCD_1812_V1.abc 164 ABC music file with the extracted tune(s)
Tune-30569-Wilson_Harmony_4NCD_1812_V1.pdf 2217 Portable Data Format
Tune-30569-Wilson_Harmony_4NCD_1812_V1.ps 6 PostScript
Tune-30569-Wilson_Harmony_4NCD_1812_V1.txt 164 Plain-text file with the extracted tune(s)
Tune-30569-get.log 5375 Log file, useful mostly for debugging
These files should be available for 24 hours.