In ICEFaces forum I've found many people with this problem. If you are using Tomcat 7.0.42, try Tomcat 7.0.41 instead and see if it works. Also check if you have icefaces jar duplicated (or icefaces.jar and icefaces-ee.jar) in the same classpath. The link to the post is:
http://www.icesoft.org/JForum/posts/list/22121.page#sthash.qxEkXX1Q.dpbs