URL Rewrite not working anymore

Hello

After having reinstalled the IIS7 Role on my Server 2008 R2 Installation, all of my URL Rewrites are not working anymore. E.g. the login rewrite for worpress:
                  

 <rule name="Rewrite Login">
                    <match url="^login(/)?$" />
                    <action type="Rewrite" url="wp-login.php" appendQueryString="false" />
</rule>

Where could be the problem?

Thanks for your help

Morrow