I'm creating a simple jsp page when I put the content type to wml (<%@ page contentType="text/vnd.wap.wml;charset=ISO-8859-1" %> it says "Content could not be encoded by the gateway". Its a pretty simple page, so I don't know what is going on.
This error message occurs when the WML is not coded properly. For example, there is a mismatch <p></p> pair etc. You need to check the WML portion. Your jsp portion should be fine otherwise the error will appear on the tomcat/webserver side.