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.
It's clear from the exception that your struts-config.xml is not right. It just doesn't help us to provide the link to a tutorial and say it's not working. If you can paste your struts-config.xml it would help.