You could simply write off this demographic, and if you're creating a personal website and don't care much about accessibility, that may work well enough for you. But if you're creating a professional website for yourself or working for a client in web design/flash animation, it would be wise of you to consider making a non-Flash alternative to the website.
I know, it sounds like a lot of work, but there's no need to start groaning just yet. If you use SSI, PHP, or any other programming language that lets you use includes, then you can easily make two copies of your layout template, one with HTML navigation, one with Flash navigation, and then simply change the name of the includes for the navigation on the non-Flash version of the site files. (This is, of course, only if you're using Flash elements in your site, rather than integrating all of the content--including text--into your Flash animation.)