Sorry, the product was not found. Ultimate SEO URLS

[yisou]

I am design a new site for my friend, say the domain is cheapglasses123.com, if visit www.cheapglasses123.com/, show error:
Sorry, the product was not found.

if visit http://www.cheapglasses123.com/index.php, every thing is ok.

[stevesh]

If that's the actual URL of the store, I'm not seeing any difference between the two.

[yisou]

Actual URL of the store is: www.bestpriceglasses.com

When visiting www.bestpriceglasses.com/index.php or
www.bestpriceglasses.com/index.html, everything is ok.

If visit www.bestpriceglasses.com only, error comes out.

[stevesh]

I'd guess you have some sort of redirection happening, maybe in an .htaccess file, or something wrong with your URL-rewriting mod.

[yisou]

before the site worked properly. any method to check.
the site is using Ultimate SEO URLs for seo.

[stevesh]

Turn off the Ultimate SEO thing and see if the problem coontinues.