Parsing of web.xml deployment descriptor failed

[Felgenhauer, Florian / DPEE extern]

Even with this simple descriptor
 
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd";>
 
<web-app>
</web-app>
 
I got 
 
Parsing of web.xml deployment descriptor failed
 
Thanks in advance for any help