I updated Jenkins to 1.540 and XShell to 0.9. Whenever I do a build I get an exception:

Started by upstream project "MyProject" build number 560
originally caused by:
Started by user Kevin Wojniak
Building on master in workspace <http://127.0.0.1:8080/job/MyProject/myproject=master/ws/>
Fetching changes from the remote Git repository
Fetching upstream changes from ssh://user@server/git/MyProject
Checking out Revision fb1f25fe51ea374f732147c9dd2fef328e1b805c (origin/master)
Cleaning workspace
Resetting working tree
FATAL: null
java.lang.NullPointerException
at java.util.regex.Pattern.<init>(Pattern.java:1132)
at java.util.regex.Pattern.compile(Pattern.java:823)
at hudson.plugins.xshell.XShellBuilder.perform(XShellBuilder.java:122)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:785)
at hudson.model.Build$BuildExecution.build(Build.java:199)
at hudson.model.Build$BuildExecution.doRun(Build.java:160)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:566)
at hudson.model.Run.execute(Run.java:1679)
at hudson.matrix.MatrixRun.run(MatrixRun.java:146)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:230)

If I downgrade to 0.8 it works fine again.