We're getting these quite often with concurrently running jobs that pull out of SVN:

java.io.IOException: Unable to delete /var/lib/jenkins/jobs/[jobname]/svnexternals.txt
at hudson.util.AtomicFileWriter.commit(AtomicFileWriter.java:112)
at hudson.XmlFile.write(XmlFile.java:174)
at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:708)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1195)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:576)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:465)
at hudson.model.Run.run(Run.java:1409)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:238)