Apache Tiles : Error : TilesContainer not initialized

We have been trying to get a simple web application that uses Apache Tiles Framework 2.0.5 to work in JDeveloper 10.1.3 .3.0.

However, we kept hitting a generic error :-

javax.servlet.jsp.JspException: TilesContainer not initialized
at org.apache.tiles.jsp.taglib.ContainerTagSupport.doStartTag
(ContainerTagSupport.java:72)
at org.apache.tiles.jsp.taglib.RenderTagSupport.doStartTag
(RenderTagSupport.java:138)
at _pets._jspService(_pets.java:48)
[/pets.jsp]
at com.orionserver[Oracle Containers for J2EE 10g (10.1.3.1.1) ].http.OrionHttpJspPage.service(OrionHttpJspPage.java:59)
at oracle.jsp.runtimev2.JspPageTable.service(JspPageTable.java:462)
at oracle.jsp.runtimev2.JspServlet.internalService(JspServlet.java:598)
at oracle.jsp.runtimev2.JspServlet.service(JspServlet.java:522)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

My friend Sriram & myself struggled to resolve this error & we were just able to resolve it.

I believe the error occurs because of these three reasons :-

1. Incorrect / Missing DTD reference in the tiles-defs.xml
2. Incorrect / Missing XML Elements in the tiles-defs.xml
3. Missing retrotranslator-runtime-n.n.n.jar in WEB-INF/lib

I am sure there are many other reasons for the error - I have just presented a quick checklist of the problems that we encountered.

The third option is still a mystery to us. I mean, why do we need to use the RetroTranslator Library when we are using JDK 1.5 ?

We are still trying to figure that one out. I'll post an update if we unravel this last mystery.