You may want to check your web.xml ... you have the filter and filter-mapping outside the web-app tag and you should not use FilterDispatcher as its been deprecated since 2.1.3 You should use probably use org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter instead.
Ok. By turning on trace, you mean debug? If yes then where should I place break points? And How can i check what is being actually deployed to the tomcat server? Honestly I've never done it.. And I've got a hunch, this is my deploying fault.
When I deploy my app for the first time, I rgiht click on project, New -> Server, and than add Tomcat. After this, I open added tomcat configuration and in Modules tab -> Add External Web Module, and from browse i set path to my app's target folder. Is it correct? Should I do this in another way? After this i start server in debug mode. The rest you already know..
EDIT: Ok, I've just figured it out Just like i thought, i deployed to tomcat the whole target folder instead of the one correct subfolder of it, with the name of my project Now it seems to work properly. Thanks very much for pointing these thigs.