when build is finished, upload with SCP plugin failed (first time we saw this).

remote folderPath ,local
file:xtr-netbeans_Dev-custom663232411-qa-t4u-sol6-1.6.0_10-rc-custom663232411-results-functional.zip
FATAL: null
java.lang.NullPointerException
at com.jcraft.jsch.Session.disconnect(Unknown Source)
at be.certipost.hudson.plugin.SCPSite.closeSession(SCPSite.java:130)
at
be.certipost.hudson.plugin.SCPRepositoryPublisher.perform(SCPRepositoryPublisher.java:121)
at
hudson.tasks.BuildStepCompatibilityLayer.perform(BuildStepCompatibilityLayer.java:33)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:309)
at
hudson.model.AbstractBuild$AbstractRunner.performAllBuildStep(AbstractBuild.java:297)
at hudson.model.Build$RunnerImpl.post2(Build.java:118)
at hudson.model.AbstractBuild$AbstractRunner.post(AbstractBuild.java:282)
at hudson.model.Run.run(Run.java:789)
at hudson.model.Build.run(Build.java:85)
at hudson.model.ResourceController.execute(ResourceController.java:70)
at hudson.model.Executor.run(Executor.java:82)