A recent upgrade to Umbraco 4.11.1. Running  It's shared hosting so I don't know if I'm on IIS 6 or 7. 

The entire site works, but when I change UmbracoSettings.config from::

        <errors>
            <!-- the id of the page that should be shown if the page is not found -->
            <!--        <errorPage culture="default">1</errorPage>-->
            <!--        <errorPage culture="en-US">200</errorPage>-->
            <error404>1</error404>
        </errors>

to:

        <errors>
            <!-- the id of the page that should be shown if the page is not found -->
            <!--        <errorPage culture="default">1</errorPage>-->
            <!--        <errorPage culture="en-US">200</errorPage>-->
            <error404>1181</error404>
        </errors>

I get the following error when I hit a page that doesn't exist. 

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Xml.XPath.XPathException: '/root//node[(contains(concat(',',translate(data [@alias='umbracoUrlAlias'], ' ', ''),','),',about-us/test,') or contains(concat(',',translate(data [@alias='umbracoUrlAlias'], ' ', ''),','),',/about-us/test,')]' has an invalid token.

Any ideas?