Can you give us more detail?
By default, Flash is not SEO-friendly.
There are ways to accomplish SEO-friendliness with a Flash site, but almost all of them are more complex than just doing a PHP code to be SEO-compatible.
For starters, your Flash file should support Deeplinking and should ideally load content off a XML file.
This, combined with some tweaks to your .htaccess files, meta keywords could make your site a wee bit more SEO-friendly.
SEO is not only about metadata written into the code. There's a lot more to it.
Your HTML Metatags will not contain all the information your Flash movie contains thereby search spiders will only crawl the title, preset description of the HTML page, not the actual flash content itself.
For Flash movie to be fully SEO friendly, you could visit this link and read about a few tips and tricks:
SEO does not simply involve meta data.
Google will sometimes use the meta description of a page in search results snippets, if we think it gives users a more accurate description than would be possible purely from the on-page content.
While this discusses the display of results, it also reveals how Google tries to interpret the page. Google falls back on meta data when there is nothing that makes sense to it between the body tags. That does not mean you can rely on meta descriptions alone. A competing site with meta descriptions and understandable content between the body tags will still rank better than yours. You've really got to get content between the body tags.
Yes, meta tags don't matter with Google. Maybe before. But because a lot of websites tried to make a fraud out of them, meta tags are no longer a criterion for ranking. Going back to the original question, Flash websites are not seo-friendly naturally. That is because spiders find it too complex.