If you didn't get any error messages or logs from Tomcat console, then you should try debug the application to find a problem. Fist thing that you should do is to turn on a developer mode: struts.devMode=true
then you will see more messages on the console.
Closer to your question: as a security issues published on the site, the DMI (Dynamic Method Invocation) has been turned off by default configuration settings. However you can change this setting to allow method:
parameter being accepted by the params
interceptor. Or you should refactor your application to use only mapped methods. For example
<action name="Login" class="test.action.LoginAction" method="login">
<result name="index">/index.jsp</result>
</action>