Looks like you did not wrap the "fork" param inside an <init-param> element.
If you did, then the complete declaration of the JspServlet in default-web.xml would look as follows:
<servlet>
<servlet-name>jsp</servlet-name>
<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
<init-param>
<param-name>xpoweredBy</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>fork</param-name>
<param-value>false</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
[Message sent by forum member 'jluehe' (jluehe)]
http://forums.java.net/jive/thread.jspa?messageID=325360