Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1793/Barsanti_CoOST.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-7724-Barsanti_CoOST.ps) >>/Users/jc/w/tmp/Tune-7724-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1793/Barsanti_CoOST.abc

Error exit status 256; here are some files to check:
[P=tuneget V=1/1 B=0 scale=0.70 512x512 PNG]
filesizedescription
Form_77243.log 871 Log file, useful mostly for debugging
Tune-7724-Barsanti_CoOST.abc 151 ABC music file with the extracted tune(s)
Tune-7724-Barsanti_CoOST.ps 6 PostScript
Tune-7724-Barsanti_CoOST.txt 151 Plain-text file with the extracted tune(s)
Tune-7724-get.log 4148 Log file, useful mostly for debugging
Tune-77242-AMHSI_abc1.abc 147 ABC music file with the extracted tune(s)
Tune-77242-AMHSI_abc1.pdf 2217 Portable Data Format
Tune-77242-AMHSI_abc1.ps 6 PostScript
Tune-77242-AMHSI_abc1.txt 147 Plain-text file with the extracted tune(s)
Tune-77242-get.log 4884 Log file, useful mostly for debugging
Tune-77243-JamesOswald_CPC-abc1.abc 157 ABC music file with the extracted tune(s)
Tune-77243-JamesOswald_CPC-abc1.pdf 2217 Portable Data Format
Tune-77243-JamesOswald_CPC-abc1.ps 6 PostScript
Tune-77243-JamesOswald_CPC-abc1.txt 157 Plain-text file with the extracted tune(s)
Tune-77243-get.log 5174 Log file, useful mostly for debugging
Tune-77249-get.log 9801 Log file, useful mostly for debugging
These files should be available for 24 hours.