[newbie] Problem subclassing TilesRequestProcessor

[ba...@solutionweb.com.br]

Hello to all!
I'm trying to subclass the TilesRequestProcessor in order to have a 
customized RequestProcessor and to support tiles in my web application, 
but the following error is showing int the browser when I call my test 
action:
java.lang.ClassCastException
                 at 
org.apache.struts.tiles.TilesRequestProcessor.initDefinitionsMapping(TilesRequestProcessor.java:126)
                 at 
org.apache.struts.tiles.TilesRequestProcessor.init(TilesRequestProcessor.java:116)
                 at 
com.ctbc.sispro.web.PropostasRequestProcessor.init(Unknown Source)
                 at 
org.apache.struts.action.ActionServlet.getRequestProcessor(ActionServlet.java:872)
                 at 
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
                 at 
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
                 at 
javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
                 at 
javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
                 at 
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)

I'm using Struts 1.1 with Tomcat 4.1.18-LE. Below is the code for my 
CustomRequestProcessor and the controller part of my struts-config.xml. I 
have already searched the Struts Users List archive for messages about 
this, but found no help.
I hope you can help me.
Thanks in advance.
Bruno.
// Customized request processor
public class CustomRequestProcessor extends TilesRequestProcessor {
  public void init(ActionServlet servlet, ModuleConfig moduleConfig) 
throws javax.servlet.ServletException {
    super.init(servlet, moduleConfig);
    initDefinitionsMapping();
  }

}

// Controller part of the struts-config.xml
 <controller debug="0" 
processorClass="com.ctbc.sispro.web.CustomRequestProcessor" />