We get this on certain jobs

path : /hudson.scm.PerJobCredentialStore
line number : 13
-------------------------------
at com.thoughtworks.xstream.converters.extended.DynamicProxyConverter.unmarshal(DynamicProxyConverter.java:92)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:63)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:76)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:60)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:137)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:33)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:926)
at hudson.util.XStream2.unmarshal(XStream2.java:80)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:912)
at hudson.XmlFile.unmarshal(XmlFile.java:148)
... 15 more
Nov 22, 2010 12:37:39 PM hudson.scm.PerJobCredentialStore <init>
INFO: Failed to retrieve Subversion credentials from /var/lib/hudson/jobs/frontend-ear-3.5/subversion.credentials
hudson.util.IOException2: Unable to read /var/lib/hudson/jobs/frontend-ear-3.5/subversion.credentials
at hudson.XmlFile.unmarshal(XmlFile.java:152)
at hudson.scm.PerJobCredentialStore.<init>(PerJobCredentialStore.java:38)
at hudson.scm.SubversionSCM$DescriptorImpl.createAuthenticationProvider(SubversionSCM.java:1707)
at hudson.scm.SubversionSCM.compareRemoteRevisionWith(SubversionSCM.java:1090)
at hudson.scm.SCM._compareRemoteRevisionWith(SCM.java:354)
at hudson.scm.SCM.poll(SCM.java:371)
at hudson.model.AbstractProject.poll(AbstractProject.java:1250)
at hudson.triggers.SCMTrigger$Runner.runPolling(SCMTrigger.java:425)
at hudson.triggers.SCMTrigger$Runner.run(SCMTrigger.java:454)
at hudson.util.SequentialExecutionQueue$QueueEntry.run(SequentialExecutionQueue.java:118)
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$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
Caused by: com.thoughtworks.xstream.converters.ConversionException: No InvocationHandler specified for dynamic proxy
---- Debugging information ----
class : com.thoughtworks.xstream.mapper.DynamicProxyMapper$DynamicProxy
required-type : com.thoughtworks.xstream.mapper.DynamicProxyMapper$DynamicProxy
path : /hudson.scm.PerJobCredentialStore
line number : 13
-------------------------------
at com.thoughtworks.xstream.converters.extended.DynamicProxyConverter.unmarshal(DynamicProxyConverter.java:92)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:82)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:63)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:76)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:60)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:137)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:33)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:926)
at hudson.util.XStream2.unmarshal(XStream2.java:80)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:912)
at hudson.XmlFile.unmarshal(XmlFile.java:148)
... 15 more