NullPointerException in jsch ChannelSession when deploying

While deploying maven-surefire-plugin for instance
I don't know if it really affects the deploy or not, everything looks fine

[INFO] [deploy:deploy]
[INFO] Retrieving previous build number from apache.snapshots
[DEBUG] adding permissions to wagon connection: 664 775
Uploading: scp://minotaur.apache.org/www/cvs.apache.org/maven-snapshot-repository/org/apache/maven/plugins/maven-surefire-plugin/2.3-SNAPSHOT/maven-surefire-plugin-2.3-20060701.160450-2.jar
12K uploaded
Exception in thread "Exec thread minotaur.apache.org" java.lang.NullPointerException
at com.jcraft.jsch.ChannelSession.run(Unknown Source)
at java.lang.Thread.run(Thread.java:619)
[INFO] Retrieving previous metadata from apache.snapshots
[DEBUG] project information for maven-surefire-plugin 2.3-20060701.160450-2 could not be found on repository: apache.snapshots
[INFO] Uploading project information for maven-surefire-plugin 2.3-20060701.160450-2
[DEBUG] adding permissions to wagon connection: 664 775