The JSP spec says the webcontainer should look up tlds by URI as referenced either directly in a JSP or as defined in web.xml within the web application itself.
Technically that means the tlds need to be provided either within a contained jar under WEB-INF/lib or else under WEB-INF/tld.
Some web containers like Tomcat go a little further and convenient than this and also search upwards in the shared classloader.
However, Websphere 6.1 is more strict to the spec and throws an exception if it cannot find the tld within the web application itself.
The jetspeed-deploy-tool already injects the portlet.tld under WEB-INF/tld (if not already existing there), but currently this is still the portlet 1.0 version.
I'll update the deployment to inject the portlet 2.0 version of portlet.tld (for portlet 1.0 backwards compatibility) as well as the new portlet_2_0.tld
Furthermore, I noticed a small glitch in the rewriter for servlet 2.3 based web.xml: the order of injected elements was incorrectly modified (by myself) and currently is no longer conforming the Servlet 2.3 DTD.
Finally, I'm going to remove the DeployMojo default setting for forcedVersion (2.3) which obviously is an incorrect default setting (should be just null, meaning the deploy-tool should auto detect the correct version).