I just submitted a patch to the gnash mailing list that makes it work in 64 bit environments. It’s just a little patch, but the elvis “testsuite” 😉 shows up and runs till the end (see screenshot) on my Athlon X2 in native 64 bit mode. Now awaiting a working browser (=Firefox) plugin – and maybe I’ll do a little bit for that as well…
Oh, maybe I forgot to mention what gnash is: A GPL implementation of the Macromedia Flash Player (v7).