This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
This looks like it might be a class loader problem. Check to see if there are any other struts jars from other versions in any common libraries that are looaded as part of the classpath within your WebLogic server.