package com.sun.faces.taglib.html_basic does not exist

When I run my web application with jetty - it works.
But when I deploy it to Tomcat 6 - I get this error:

SEVERE: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: PWC6033: Error in Javac compilation for JSP

PWC6197: An error occurred at line: 20 in the jsp file: /pages/mainpage.jsp
PWC6199: Generated servlet error:
package com.sun.faces.taglib.jsf_core does not exist

I do not understand anything. Pleas help. I will give all information you need.

Did you add all the required JSF JAR files to your application's WEB-INF/lib folder?

Rob Spoor wrote:Did you add all the required JSF JAR files to your application's WEB-INF/lib folder?

Yes, I have jsf-impl.jar and jsf-api.jar in WEB-INF/lib folder.
Application work on jetty, so I think I added all libraries I need.