Hello Baz Matt ,
First I want you to check 2 things,
1) Are you trying to access the
JSP page directly with the struts tags ? Sometimes this error arises due to directly accessing the JSP and not letting the Dispatcher to initialize the request processing cycle and create needed value stack. In this case , you will have to write an action class that you will initialy hit which will then render the JSP page for you.
2) My second guess is the filterDispatcher. This may be the cause of the issue and I am just sharing my experience because I spent countless hours to determine the solution to this problem when I started learning struts. In the web.xml you have defined the filterDispatcher as
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter , try changing this to the old dispatcher
org.apache.struts2.dispatcher.FilterDispatcher. Again , this step is just a wild guess I am taking , it may or may not solve your problem.
3) what URL do you type to invoke your action ?