if jou use the Facelets, you must delete for Tomcat 6 el-api.jar, el-ri.jar und couse jsp2.0.jar
thank you, but i don't use facelets
This is just a guess.
A friend had a similar problem with tomcat 5.5 when updating to 3.2.0 when using eclipse.
He solved his problem by running a "mvn eclipse:clean eclipse:eclipse" and then a refresh on the project (or perhaps a restart).
So maybe your IDE is caching something?