I think theres a conflict whith another .jar of TOMCAT. How can i resolve my problem ??
If you are using Tomcat 3.2.x yes, the problem is a JAXP version conflict. Tomcat, in fact, is using the old JAXP 1.0. I think that Tomcat 4 will use the latest version. I cannot guarantee, but you can try to put the new jar in the WEB-INF/lib directory of your context. They will be added (i thing is preponed) to the main classpath after the servlet engine is started (and the configuration files have all been read). It could be a temporary solution until the new Tomcat (actually in beta 3) will go final.