I can process the first XSL-FO document. But the following XSL-FO documents fail with the same error: ClassNotFound on javax.xml.transform.Transformer.
It seems -but I'm not sure yet- that I only have this problem when I process the following documents from a different thread.
Tomcat 4.0.3 has problems with the classloader. If you have to use it, move the FOP jars into the Tomcat lib directory. It is recommended to upgrade to 4.0.4