Web project doesn't run on Eclipse's Tomcat

Question

I have a J2EE web project, using Struts and Hibernate. It worked out perfectly on my development enviroment until few days ago (I really don't know what happened, I didn't touch anything..), when it stopped running on Eclipse's tomcat server. I'm using Eclipse Java EE kepler, JRE 6 and Tomcat 5.5.36. The project runs fine on an external Tomcat 5.5.36 but when I run it on Eclipse I get:

404 - The requested resource is not available.

The Console trace is:

26-nov-2013 13:43:12 org.apache.catalina.core.AprLifecycleListener init
   INFO: The APR based Apache Tomcat Native library which allows optimal performance in       production environments was not found on the java.library.path: C:\Program    Files\Java\jre6\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;......
   26-nov-2013 13:43:14 org.apache.coyote.http11.Http11BaseProtocol init
   INFO: Inicializando Coyote HTTP/1.1 en puerto http-8080
   26-nov-2013 13:43:14 org.apache.catalina.startup.Catalina load
   INFO: Initialization processed in 4942 ms
   26-nov-2013 13:43:14 org.apache.catalina.core.StandardService start
   INFO: Arrancando servicio Catalina
   26-nov-2013 13:43:14 org.apache.catalina.core.StandardEngine start
   INFO: Starting Servlet Engine: Apache Tomcat/5.5.36
   26-nov-2013 13:43:14 org.apache.catalina.core.StandardHost start
   INFO: Desactivada la validación XML
   26-nov-2013 13:43:16 org.apache.catalina.core.StandardContext start
   GRAVE: Error filterStart
   26-nov-2013 13:43:16 org.apache.catalina.core.StandardContext start
   GRAVE: Falló en arranque del Contexto [/phnemos_ph] debido a errores previos
   26-nov-2013 13:43:17 org.apache.coyote.http11.Http11BaseProtocol start

The error is:

startup failed due to previous errors

But I can't trace it further because Tomcat's localhost log is empty, it exists but empty.

This is my web.xml:

<jsp-config>
  <jsp-property-group>
    <url-pattern>*.jsp</url-pattern>
    <trim-directive-whitespaces>true</trim-directive-whitespaces>
  </jsp-property-group>
</jsp-config>


<display-name>PH Web Application</display-name>

<!-- Action Servlet Configuration -->
<servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>com.tsystems.web.common.MyFrontController</servlet-class>
    <init-param>
        <param-name>config</param-name>
        <param-value>/WEB-INF/struts-config.xml</param-value>
    </init-param>
    <init-param>
        <param-name>debug</param-name>
        <param-value>2</param-value>
    </init-param>
    <init-param>
        <param-name>detail</param-name>
        <param-value>2</param-value>
    </init-param>
    <load-on-startup>2</load-on-startup>
</servlet>




<!-- Action Servlet Mapping -->
<servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>




<!-- The Welcome File List -->
<welcome-file-list>
    <welcome-file>paginas/index.jsp</welcome-file>
</welcome-file-list>

<!-- Struts Tag Library Descriptor -->
<taglib>
    <taglib-uri>struts-app</taglib-uri>
    <taglib-location>/WEB-INF/app.tld</taglib-location>
</taglib>

<taglib>
    <taglib-uri>struts-tiles</taglib-uri>
    <taglib-location>/WEB-INF/struts-tiles.tld</taglib-location>
</taglib>

<taglib>
    <taglib-uri>struts-bean</taglib-uri>
    <taglib-location>/WEB-INF/struts-bean.tld</taglib-location>
</taglib>

<taglib>
    <taglib-uri>struts-logic</taglib-uri>
    <taglib-location>/WEB-INF/struts-logic.tld</taglib-location>
</taglib>

<taglib>
    <taglib-uri>struts-html</taglib-uri>
    <taglib-location>/WEB-INF/struts-html.tld</taglib-location>
</taglib>

<taglib>
    <taglib-uri>struts-nested</taglib-uri>
    <taglib-location>/WEB-INF/struts-nested.tld</taglib-location>
</taglib>

<!-- Declaraci�n de filtros-->

  <filter>
    <filter-name>Filtro de Seguridad</filter-name>
    <filter-class>com.tsystems.web.common.FiltroSeguridad</filter-class>
  </filter>

<!--   Mapeo de filtros.Asociamos el filtro al jsp Menu.jsp-->

  <filter-mapping>
    <filter-name>Filtro de Seguridad</filter-name>
    <url-pattern>*.do</url-pattern> 
  </filter-mapping>

    <filter-mapping>
    <filter-name>Filtro de Seguridad</filter-name>
    <url-pattern>*.jsp</url-pattern> 
  </filter-mapping> 

<!--  
 <security-constraint>
    <web-resource-collection>
    <web-resource-name>Paginas de gestion de preferencias de usuario</web-resource-name>
    <url-pattern>/*</url-pattern>
    <http-method>DELETE</http-method>
    <http-method>GET</http-method>
    <http-method>POST</http-method>
    <http-method>PUT</http-method>
    </web-resource-collection>
    <auth-constraint>
    <role-name>OPER_CPH</role-name>
    </auth-constraint>
  </security-constraint>

    <login-config>
    <auth-method>FORM</auth-method>
    <form-login-config>
      <form-login-page>/paginas/login/login2.jsp</form-login-page>
      <form-error-page>/paginas/login/login2.jsp</form-error-page>
    </form-login-config>
  </login-config>

  <security-role>
    <description>Operador</description>
    <role-name>OPER_CPH</role-name>
  </security-role>
-->

<listener>
    <listener-class>com.tsystems.contextListener.ContextListener</listener-class>
</listener>

</web-app>

Please, any little help would be great because I'm stuck since several days. Thank you!!