Struts 1.3.10 error

[Chris Pat]

Hello
I get the following when trying to forward to a frameset that is already up and presenting content to the client. I know the for global forwards is correct, it work the first time in the default. Can someone help me explain why this failure?

protected ForwardConfig execute(ActionContext context, Action action, ActionConfig actionConfig, ActionForm actionForm) throws Exception { return null;}