NPE in Workspace clean-up thread - ClearCase

[Laura]

We are using Jenkins 1.408 and ClearCase plugin 1.3.5, on Windows XP
Our old workspaces are not getting cleaned up, even after a month, and
faithfully once a day the log reports:

INFO: Started Workspace clean-up
Exception in thread "Workspace clean-up thread"
java.lang.NullPointerException
at
hudson.plugins.clearcase.AbstractClearCaseScm.processWorkspaceBeforeDeletion(AbstractClearCaseScm.java:
591)
at
hudson.model.WorkspaceCleanupThread.shouldBeDeleted(WorkspaceCleanupThread.java:
124)
at
hudson.model.WorkspaceCleanupThread.process(WorkspaceCleanupThread.java:
144)
at
hudson.model.WorkspaceCleanupThread.execute(WorkspaceCleanupThread.java:
74)
at hudson.model.AsyncPeriodicWork$1.run(AsyncPeriodicWork.java:51)
at java.lang.Thread.run(Unknown Source)

It looks a heck of a lot like
http://issues.hudson-ci.org/browse/HUDSON-5030
including the stack trace, the use of slave agents, and the use of
variable names in the view name.
Some of our slaves, including the busiest one with the most old
workspaces, are running on the same system as the master, if this
makes any difference.

Any ideas what might be going on? Has a bug risen from the dead?