After upgrading to 1.343, I see in the Hudson log:

Jan 30, 2010 4:42:09 PM hudson.init.InitializerFinder getDisplayNameOf
WARNING: Failed to load hudson.model.queue.Messages for public static void hudson.model.queue.QueueSorter.installDefaultQueueSorter()
java.lang.ClassNotFoundException: hudson.model.queue.Messages
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at winstone.classLoader.WebappClassLoader.loadClass(WebappClassLoader.java:83)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at hudson.init.InitializerFinder.getDisplayNameOf(InitializerFinder.java:84)
at hudson.init.InitializerFinder$TaskImpl.getDisplayName(InitializerFinder.java:160)
at hudson.model.Hudson$4.onTaskCompleted(Hudson.java:688)
at org.jvnet.hudson.reactor.ReactorListener$Aggregator.onTaskCompleted(ReactorListener.java:71)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:188)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)