servlet-api-2.4.jar not loaded with tomcat 6.0.16

[Michael Ströder]

HI!

It seems the cas-server-webapp 3.3 does not work with my configuration
under tomcat 6.0.16:

catalina.out contains:
---------------------------------------------------------------------------
INFO:
validateJarFile(/usr/share/tomcat6/webapps/casextern/WEB-INF/lib/servlet-api-2.4.jar)
- jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class:
javax/servlet/Servlet.class
---------------------------------------------------------------------------

Anyone here having an idea what's the issue is?

Ciao, Michael.