htaccess server problem

[mvnr_83]

Hi all
i have some probelm with htacess
i am using php 4.0.and i am getting 500 internal error when i use the follwing code.
is the problem with server version or code i used?

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_URI} !index.php
RewriteRule ^([a-zA-Z0-9_-]+).php$ index.php?action=$1
RewriteRule ^admin/([a-zA-Z0-9_-]+).php$ admin/index.php
</IfModule>

Please help me.

[auxone]

that !index.php could probably use a != instead. i do != personally so i dont know if just ! works.