Flash is working fine at that site for me with SeaMonkey 1.1.14 on VL 5.9 Standard.
You don't need a package for Flash. Just go to http://get.adobe.com/flashplayer/?promoid=BUIGP
and select .tar.gz in the "Select version to download..." dropdown. Expand that file with your file manager (I use Midnight Commander) after it downloads. You'll get two files in a /install_flash_player_10_linux directory. Don't bother with flashplayer-installer, as it hasn't worked for me. Instead, as root simply copy libflashplayer.so into /usr/lib/mozilla/plugins, replacing the libflashplayer.so that's there. (I strongly suggest backing up the old libflashplayer.so before replacing it with the new one.) If you want all users to have access to Flash, have ownership set to root as owner and group, and permissions set to read, write execute by owner, read and execute by group, read and execute by others. There should be a symlink to this libflashplayer.so in /opt/seamonkey/lib/seamonkey-1.1.14/plugins. Start SeaMonkey and you should have the latest Flash working.
This plugin installation will also work with Firefox. Opera 9.6x in VL 5.9 Standard does not work with Flash 10. It does work with the earlier Flash, but there is a big security hole in that Flash. So if I need Flash at a site, I launch SeaMonkey and use that. Flash 10 and Opera are working in VL 6 Standard.