This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
This problem could be caused by the struts.jar file being loaded by another Class loader. Check to make sure that there isn't another copy of the struts.jar file in one of the App Server's common libraries.