Internationalization issue

Hi,

How can I get a simple Internationalization tag work. I use the following
JSP:

<%@(protected)"%>
<%@(protected)"%>

<%-- I18N Formatting --%>

<%@(protected)" %>
<html>
<head><title>Localized JSP Page</title></head>
<body>
<p>
Sample localized message:
<fmt:bundle basename="index">
<fmt:message key="hello_world"/>
</fmt:bundle>
</p>
</body>
</html>

I put a index.properties containing a hello_world key in the root of my war
and in WEB-INF/classes,
But I obtain the following stack trace:

org.apache.jasper.JasperException: jsp.error.beans.property.conversion

org.apache.jasper.runtime.JspRuntimeLibrary.getValueFromPropertyEditorManage
r(JspRuntimeLibrary.java:931)

org.apache.jsp.index_jsp._jspx_meth_fmt_message_0(index_jsp.java:119)
org.apache.jsp.index_jsp._jspService(index_jsp.java:76)
org.apache.jasper.runtime.HttpJspBase.service (HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service (HttpServlet.java:856)

org.apache.jasper.servlet.JspServletWrapper.service (JspServletWrapper.java:3
11)

org.apache.jasper.servlet.JspServlet.serviceJspFile (JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service (JspServlet.java:248)
javax.servlet.http.HttpServlet.service (HttpServlet.java:856)

org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter
.java:305)

Can anyone help ?

Cheers.