Macromedia's Flash player for Linux won't work out of the box on AMD64. This link has directions for getting Firefox 2.0, Flock, IceWeasel to run in 32 bit mode for the purpose of using Flash9 with sound and Java. These instructions assume that you're using Dapper or Edgy AMD64, though other versions may work too. It works great!!! It will not conflict with your 64bit browser.
http://www.ubuntuforums.org/showthread. ... light=java