Mod_rewrite not work

hi all,
i have a php website and i want to replace php extensions to html

can anybody help me?
im using this

Options +FollowSymLinks RewriteEngine On RewriteRule ^my-age-([0-9]+).html /my-age.php?age=$1 [QSA,L]

but it not work
in forefox it show this error:

[code]The page isn’t redirecting properly

Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

This problem can sometimes be caused by disabling or refusing to accept cookies.[/code]

and in chrome it show this:

[code]The page isn’t working redirected you too many times.

please help
thank you!