Trinidad JSF tr:panelPopup opened by js is not working in IE

Question

I'm using Trinidad 1.2.12. I have a jsp page that has a tr:panelPopup. I need to open the popup in certain cases when the page is reloaded. I tried to do this by placing a panelGroupLayout with the appropiate render attribute. Inside of that panel I have the tr:panelPopup and a js function that calls the function that shows the popup. This work fine in Firefox and Chrome, but it doesn't work in IE 6 nor IE 7. The js is triggered and the js function is showing the popup but then an error message is shown saying something like "Internet explorer can't open the site http://."

I have created a small example that illustrates the problem:

<?xml version="1.0" encoding="UTF-8"?>
<ui:composition xmlns:jsp="http://java.sun.com/JSP/Page"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:trh="http://myfaces.apache.org/trinidad/html"
    xmlns:tr="http://myfaces.apache.org/trinidad"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    template="/WEB-INF/template/plantillaFormularios.xhtml"
    xmlns:t="http://myfaces.apache.org/tomahawk"&gt;
    <ui:define name="contenido">
    <tr:panelPopup id="popupMensajes" modal="true" position="centered" title="Mensaje de la aplicación">
      <tr:panelGroupLayout layout="vertical" inlineStyle="height:200px; width:300px; background-color: #fff000;">
       <tr:outputText value="MENSAJE"></tr:outputText>
      </tr:panelGroupLayout>
    </tr:panelPopup>
    <tr:commandButton id="btn" inlineStyle="visibility: hidden;"
     onclick="TrPanelPopup.showPopup('popupMensajes_popupContainer', 'popupMensajes', event, 'click','centered',true,0,0,0,0); return false;"></tr:commandButton>
    <trh:script text="document.getElementById ('btn').click();"></trh:script>

    </ui:define>
</ui:composition>