config.getInitParameter always return null

Why does config.getInitParameter(String) always return null in the following code example?

public void init(ServletConfig config) throws ServletException{    super.init(config);    filename = config.getInitParameter("addressfile");

This is web.xml file

<servlet><servlet-name>ListManagerServlet</servlet-name><servlet-class>savva.listmanagerservlet.ListManagerServlet</servlet-class><init-param><param-name>addressfile</param-name><param-value>d:\temp\demo.txt</param-value></init-param></servlet><servlet-mapping><servlet-name>ListManagerServlet</servlet-name><url-pattern>/ListManagerServlet</url-pattern></servlet-mapping>

UPD: Eclipse EE Indigo, Java 1.6, Tomcat 7.0