NamingException running Cactus tests

I am trying to make Cactus with the Ant Integration work in my
environment for the first time.

I have installed Tomcat 5.5 and Cactus jakarta-cactus-13-1.7.1.

When I run "ant test" I get the exception below in tomcat5x.out and the
test hangs.

Your help will be very much appreciated.

Thank you,
Francesco

Mar 21, 2006 2:16:43 PM org.apache.catalina.realm.UserDatabaseRealm
start
SEVERE: Exception looking up UserDatabase under key UserDatabase
javax.naming.NamingException: Cannot create resource instance
	at
org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFact
ory.java:142)
	at
javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
	at
org.apache.naming.NamingContext.lookup(NamingContext.java:792)
	at
org.apache.naming.NamingContext.lookup(NamingContext.java:152)
	at
org.apache.catalina.realm.UserDatabaseRealm.start(UserDatabaseRealm.java
:253)
	at
org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1005)
	at
org.apache.catalina.core.StandardEngine.start(StandardEngine.java:442)
	at
org.apache.catalina.core.StandardService.start(StandardService.java:450)
	at
org.apache.catalina.core.StandardServer.start(StandardServer.java:709)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:551)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)
	at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at
org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:275)
	at
org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Mar 21, 2006 2:16:43 PM org.apache.catalina.startup.Catalina start
SEVERE: Catalina.start: 
LifecycleException:  No UserDatabase component found under key
UserDatabase
	at
org.apache.catalina.realm.UserDatabaseRealm.start(UserDatabaseRealm.java
:261)
	at
org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1005)
	at
org.apache.catalina.core.StandardEngine.start(StandardEngine.java:442)
	at
org.apache.catalina.core.StandardService.start(StandardService.java:450)
	at
org.apache.catalina.core.StandardServer.start(StandardServer.java:709)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:551)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)
	at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:585)
	at
org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:275)
	at
org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
Mar 21, 2006 2:16:43 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 510 ms