Tests results are lost since 1.337 (or maybe 1.336 since I went from 1.335 to 1.337).
Tests results are produced in Junit format and collected with "Publish JUnit tests reports results" option.

This is the error message as displayed in Console Output:

Recording test results
ERROR: Failed to archive test reports
hudson.util.IOException2: remote file operation failed
at hudson.FilePath.act(FilePath.java:672)
at hudson.FilePath.act(FilePath.java:660)
at hudson.tasks.junit.JUnitResultArchiver.perform(JUnitResultArchiver.java:117)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:583)
at hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:564)
at hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:551)
at hudson.model.Build$RunnerImpl.post2(Build.java:152)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:535)
at hudson.model.Run.run(Run.java:1202)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:122)
Caused by: hudson.util.IOException2: Failed to read /home/hudson-dec/hudson/workspace/Archi-1.5_lenny64/PLEIADES/TEST-arch.xml
at hudson.tasks.junit.TestResult.parse(TestResult.java:195)
at hudson.tasks.junit.TestResult.parse(TestResult.java:136)
at hudson.tasks.junit.TestResult.<init>(TestResult.java:99)
at hudson.tasks.junit.JUnitResultArchiver$ParseResultCallable.invoke(JUnitResultArchiver.java:234)
at hudson.tasks.junit.JUnitResultArchiver$ParseResultCallable.invoke(JUnitResultArchiver.java:209)
at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2062)
at hudson.remoting.UserRequest.perform(UserRequest.java:104)
at hudson.remoting.UserRequest.perform(UserRequest.java:48)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$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:619)
Caused by: org.dom4j.DocumentException: null Nested exception: null
at org.dom4j.io.SAXReader.read(SAXReader.java:484)
at org.dom4j.io.SAXReader.read(SAXReader.java:264)
at hudson.tasks.junit.SuiteResult.parse(SuiteResult.java:93)
at hudson.tasks.junit.TestResult.parse(TestResult.java:180)
... 14 more
Caused by: java.lang.NullPointerException
at org.dom4j.io.SAXHelper.createXMLReader(SAXHelper.java:98)
at org.dom4j.io.SAXReader.createXMLReader(SAXReader.java:894)
at org.dom4j.io.SAXReader.getXMLReader(SAXReader.java:715)
at org.dom4j.io.SAXReader.read(SAXReader.java:435)
... 17 more
Sending e-mails to: <hidden mail>
Build failed. Publishing Doxygen skipped.
Finished: FAILURE

And the corresponding node log :

[12/16/09 12:59:34] [SSH] Checking java version of java
[12/16/09 12:59:34] [SSH] java -version returned 1.6.0_12.
[12/16/09 12:59:34] [SSH] Starting sftp client.
[12/16/09 12:59:34] [SSH] Copying latest slave.jar...
[12/16/09 12:59:35] [SSH] Copied 212,574 bytes.
[12/16/09 12:59:35] [SSH] Starting slave process: cd '/home/hudson-dec/hudson' && java -jar slave.jar
<===[HUDSON REMOTING CAPACITY]===>channel started
Slave.jar version: 1.337 (private-12/11/2009 03:49-kohsuke)
This is a Unix slave
Copied maven-agent.jar
Copied maven-interceptor.jar
Copied maven2.1-interceptor.jar
Warning: Caught exception attempting to use SAX to load a SAX XMLReader
Warning: Exception was: java.lang.NullPointerException
Warning: I will print the stack trace then carry on using the default SAX parser
java.lang.NullPointerException
at hudson.remoting.RemoteClassLoader$ClassLoaderProxy.hashCode(RemoteClassLoader.java:396)
at java.util.HashMap.get(HashMap.java:343)
at hudson.remoting.ExportTable.export(ExportTable.java:155)
at hudson.remoting.Channel.export(Channel.java:468)
at hudson.remoting.RemoteClassLoader.exportId(RemoteClassLoader.java:318)
at hudson.remoting.RemoteClassLoader$ClassLoaderProxy.fetch2(RemoteClassLoader.java:350)
at sun.reflect.GeneratedMethodAccessor1157.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at hudson.remoting.RemoteInvocationHandler$RPCRequest.perform(RemoteInvocationHandler.java:274)
at hudson.remoting.Request$2.run(Request.java:270)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:417)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:269)
at java.util.concurrent.FutureTask.run(FutureTask.java:123)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
at java.lang.Thread.run(Thread.java:595)