Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/1791/MichaelDabney_12Minuets12Dances-1760-V2.abc"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-9186-MichaelDabney_12Minuets12Dances-1760-V2.ps) >>/Users/jc/w/tmp/Tune-9186-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/1791/MichaelDabney_12Minuets12Dances-1760-V2.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-9186-MichaelDabney_12Minuets12Dances-1760-V2.abc 176 ABC music file with the extracted tune(s)
Tune-9186-MichaelDabney_12Minuets12Dances-1760-V2.ps 6 PostScript
Tune-9186-MichaelDabney_12Minuets12Dances-1760-V2.txt 176 Plain-text file with the extracted tune(s)
Tune-9186-get.log 4675 Log file, useful mostly for debugging
Tune-91869-2431_Uncle_Toms_Jig-001.svg 13377 Scalable Vector Graphics format
Tune-91869-2431_Uncle_Toms_Jig.abc 361 ABC music file with the extracted tune(s)
Tune-91869-2431_Uncle_Toms_Jig.txt 361 Plain-text file with the extracted tune(s)
Tune-91869-WilliamCampbell_10thBook_1798-V2.abc 169 ABC music file with the extracted tune(s)
Tune-91869-WilliamCampbell_10thBook_1798-V2.pdf 2217 Portable Data Format
Tune-91869-WilliamCampbell_10thBook_1798-V2.ps 6 PostScript
Tune-91869-WilliamCampbell_10thBook_1798-V2.txt 169 Plain-text file with the extracted tune(s)
Tune-91869-get.log 9798 Log file, useful mostly for debugging
These files should be available for 24 hours.