I feel your pain. It took me a while to set up a struts 2 project in eclipse Juno, the main problem being that there is no definitive list of what jars to use. I haven't got time to study the .xml files but list the jars I am using in my project which also has tiles 2 and it took me a while to get the jars so it all works. (I am not sure the 3 asm jars are needed but if it is working, I have left them in).
It is best if you use "struts2-blank.war" to start your new project as it contains all basic jar files with proper compatible version. "struts2-blank.war" is provided by apache with Full distribution and Example Applications. this way many initial difficulties involving mismatch of libraries can be avoided.