Look for server errors specifically.
Just to be sure, you should also be able to deploy and use one of the sample application provided with your struts release.
More struts specifically, if you use struts taglibs in your JSPs check if you
have added struts-html.tld at correct path.
If you use forms in your JSPs, put action attribute in form tag and check it
matches the same entry in your struts-config file (check your action mapping is correct).