We are moving our builds from Hudson on server A to Hudson on server B. Both servers are running
Hudson 1.252 on JDK 1.6.0_10-beta and Tomcat 6.0.14.

Builds on the master run just fine. However, we have a server C that's set up as a slave processor; jobs
run by Hudson on server A run fine, but jobs run by Hudson on server B always throw this error:

started
Building remotely on C
Updating svn+ssh://svn.example.com/svn/repos/project/trunk
ERROR: Failed to update svn+ssh://svn.example.com/svn/repos/project/trunk
org.tmatesoft.svn.core.SVNCancelException: svn: No credential to try. Authentication failed
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.cancel(SVNErrorManager.java:36)
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.cancel(SVNErrorManager.java:31)
at
org.tmatesoft.svn.core.internal.wc.DefaultSVNAuthenticationManager.getFirstAuthentication(DefaultSVN
AuthenticationManager.java:167)
at org.tmatesoft.svn.core.internal.io.svn.SVNSSHConnector.open(SVNSSHConnector.java:70)
at org.tmatesoft.svn.core.internal.io.svn.SVNConnection.open(SVNConnection.java:73)
at
org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.openConnection(SVNRepositoryImpl.java:1229
)
at
org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.testConnection(SVNRepositoryImpl.java:94)
at org.tmatesoft.svn.core.io.SVNRepository.getRepositoryUUID(SVNRepository.java:273)
at org.tmatesoft.svn.core.wc.SVNBasicClient.createRepository(SVNBasicClient.java:301)
at org.tmatesoft.svn.core.wc.SVNBasicClient.createRepository(SVNBasicClient.java:289)
at org.tmatesoft.svn.core.wc.SVNUpdateClient.doUpdate(SVNUpdateClient.java:221)
at org.tmatesoft.svn.core.wc.SVNUpdateClient.doUpdate(SVNUpdateClient.java:159)
at org.tmatesoft.svn.core.wc.SVNUpdateClient.doUpdate(SVNUpdateClient.java:155)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:442)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:413)
at hudson.FilePath$FileCallableWrapper.call(FilePath.java:1176)
at hudson.remoting.UserRequest.perform(UserRequest.java:69)
at hudson.remoting.UserRequest.perform(UserRequest.java:23)
at hudson.remoting.Request$2.run(Request.java:213)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)
finished: FAILURE

I am able to:
1. log into B and su to the user running Hudson
2. ssh as that user to C
3. cd ~/.hudson/workspace/project
4. svn co svn+ssh://svn.example.com/svn/repos/project/trunk project

without any errors or prompts.

Is there a way to turn on additional logging or something, to get a better idea why the slave run from
one master works but the other one doesn't?