b5 crash on startup (b4 ok...)

Hi, With b5, I'm getting: 08:40:44,392 ERROR main [/xwiki]:listenerStart:3767 - Exception sending context initialized event to listener instance of class com.xpn.xwiki.web.InitializationServletContextLi stener ... Caused by: java.lang.NullPointerException at com.xpn.xwiki.util.XWikiVelocityUberspector.init(XWikiVelocityUberspector.java:57) at org.apache.velocity.runtime.RuntimeInstance.initializeIntrospection(RuntimeInstance.java:289) at org.apache.velocity.runtime.RuntimeInstance.init(RuntimeInstance.java:231) at org.apache.velocity.runtime.RuntimeSingleton.init(RuntimeSingleton.java:114) at org.apache.velocity.app.Velocity.init(Velocity.java:80) at com.xpn.xwiki.web.InitializationServletContextListener.initializeVelocity(InitializationServletContextListener.java:88) at com.xpn.xwiki.web.InitializationServletContextListener.contextInitialized(InitializationServletContextListener.java:44) ... 24 more Mar 7, 2007 8:40:44 AM org.apache.catalina.core.StandardContext start SEVERE: Error listenerStart Mar 7, 2007 8:40:44 AM org.apache.catalina.core.StandardContext start SEVERE: Context [/xwiki] startup failed due to previous errors Anything special I should look at? B4 started up OK. My environment is: Linux 2.6.15-28-686 java version "1.6.0" Java(TM) SE Runtime Environment (build 1.6.0-b105) Java HotSpot(TM) Client VM (build 1.6.0-b105, mixed mode, sharing) Apache Tomcat/5.5.20 -Thanks, -Tom -- May 4, 1970: Alison Krause, Jeffrey Miller, Sandra Scheuer, William Schroeder.