Why doesn't security work for Tomcat 6.0.14

[sex]

I'm trying to give myself access to the manager web app, but have been =
unsuccessful.  My tomcat-users.xml looks like this:

<?xml version='1.0' encoding='utf-8'?>
<tomcat-users>
  <role rolename="manager"/>
  <role rolename="admin"/>
  <user username="chris" password="chris" roles="admin,manager"/>
</tomcat-users>


but I always get a "401 Unauthorized" error.  Any ideas?