After enabling the deployment of my artifact on my private CloudBees snapshot repository, I get this error when I build my project :

[cloudbees-deployer] Deploying myapp
java.lang.NullPointerException
at com.cloudbees.plugins.deployer.engines.Engine.perform(Engine.java:89)
at com.cloudbees.plugins.deployer.DeployBuilder.perform(DeployBuilder.java:80)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:727)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.build(MavenModuleSetBuild.java:866)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.doRun(MavenModuleSetBuild.java:805)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:509)
at hudson.model.Run.execute(Run.java:1505)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:477)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:236)

My project is a simple war project (with GWT).