I'm trying to configure FileServlet in web.xml as described
on the FileContent module configuration page. However I'm getting this
error:

SEVERE: Parse error in application web.xml file at jndi:/localhost/WEB-INF/web.xml
java.lang.IllegelArgumentException: addChild: Child name 'FileServlet' is not unique


This was caused by adding the following lines to web.xml

    <servlet>
        <servlet-name>FileServlet</servlet-name>
        <servlet-class>org.labkey.api.view.FileServlet</servlet-class>
    </servlet>

    <servlet-mapping>
            <servlet-name>FileServlet</servlet-name>
            <url-pattern>/files/*</url-pattern>
        </servlet-mapping>

Any ideas what's causing this?

Dan