I've noticed this error after upgrading from Hudson 1.318 to 1.320. Anyone
know what the problem is, or how best to troubleshoot it?

Last Subversion Polling Log
Started on Aug 24, 2009 5:56:09 PM
Remote call failed
java.io.IOException: Remote call failed
at hudson.remoting.Channel.call(Channel.java:520)
at hudson.scm.SubversionSCM.pollChanges(SubversionSCM.java:974)
at hudson.model.AbstractProject.pollSCMChanges
(AbstractProject.java:965)
at hudson.triggers.SCMTrigger$Runner.runPolling(SCMTrigger.java:312)
at hudson.triggers.SCMTrigger$Runner.run(SCMTrigger.java:339)
at hudson.util.SequentialExecutionQueue$QueueEntry.run
(SequentialExecutionQueue.java:114)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown
Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: Failed to deserialize the Callable
object. Perhaps you needed to implement DelegatingCallable?
at hudson.remoting.UserRequest.perform(UserRequest.java:89)
at hudson.remoting.UserRequest.perform(UserRequest.java:47)
at hudson.remoting.Request$2.run(Request.java:236)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown
Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:54)
... 1 more
Caused by: java.lang.ClassNotFoundException:
hudson.plugins.trac.TracRepositoryBrowser
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at com.sun.jnlp.JNLPClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at java.io.ObjectInputStream.resolveClass(Unknown Source)
at hudson.remoting.ObjectInputStreamEx.resolveClass
(ObjectInputStreamEx.java:52)
at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
at java.io.ObjectInputStream.readClassDesc(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.defaultReadFields(Unknown Source)
at java.io.ObjectInputStream.readSerialData(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.defaultReadFields(Unknown Source)
at java.io.ObjectInputStream.readSerialData(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
at hudson.remoting.UserRequest.perform(UserRequest.java:87)
... 9 more
Done. Took 0.5 sec
No changes