Just ran into this problem. Seems like the checksums file for Flash version 24.0.0.194 hasn't been uploaded (this is the file located at http://people.debian.org/~bartm/flashplugin-nonfree/D5C0FC14/fp.24.0.0.194.sha512.amd64.pgp.asc). Having a gander at the directory it looks the i386 version is absent as well so looks like it just hasn't been uploaded yet.
The necessary URIs and steps to work around this can be worked out by looking at the `update-flashplugin-nonfree` script, but not including specifics as I can't find anyway to verify the download files so this is done at your own risk. If anyone knows another place we can get checksums for the blobs from Adobe that would be helpful. Cheers, Aubrey
