How do I fix Jenkins Team Concert Plugin java.lang.IllegalArgumentException at com.ibm.team.filesystem.client.internal.Shareable.(Shareable.java:72)?

I have Jenkins 1.509.2 with Team Concert Plugin 1.0.12 and RTC Build Toolkit 4.0.4 and when I run a build (linked to an RTC Build Definition) it does the Checkout (accept + load/synchronize) once or twice, but around the third build I start getting the error and I will get it on every build until I wipe the Jenkins workspace clean. What's wrong? I am seeing the same behaviour on two different unix platforms (Mac OSX, Linux X64).

RTC : checkout...
RTC Checkout : Source control setup
RTC Checkout : Accepting changes into workspace "Build-MacOSX Workspace" ...
RTC Checkout : Fetching files to fetch destination "/Users/foo/jenkins/workspace/Build-MacOSX" ...
FATAL: RTC : checkout failure: null
java.lang.IllegalArgumentException
	at com.ibm.team.filesystem.client.internal.Shareable.<init>(Shareable.java:72)
	at com.ibm.team.filesystem.client.internal.SharingManager.getLocalFileStorage(SharingManager.java:1080)
	at com.ibm.team.filesystem.client.internal.load.MergeLoadMutator$4.run(MergeLoadMutator.java:1603)
	at com.ibm.team.filesystem.client.internal.SharingManager.doSilentChange(SharingManager.java:775)
	at com.ibm.team.filesystem.client.internal.load.MergeLoadMutator.deleteSubtree(MergeLoadMutator.java:1568)
	at com.ibm.team.filesystem.client.internal.load.MergeLoadMutator.removeExtraneousContent(MergeLoadMutator.java:972)
	at com.ibm.team.filesystem.client.internal.load.MergeLoadMutator.load(MergeLoadMutator.java:819)
	at com.ibm.team.filesystem.client.internal.load.MergeLoadMutator.execute(MergeLoadMutator.java:313)
	at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.run(FileSystemOperation.java:89)
	at com.ibm.team.filesystem.client.internal.operations.LoadOperation.load(LoadOperation.java:1047)
	at com.ibm.team.filesystem.client.internal.operations.LoadOperation$1.run(LoadOperation.java:664)
	at com.ibm.team.filesystem.client.internal.SharingManager.runWithinFileSystemLock(SharingManager.java:935)
	at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.runWithinFileSystemLock(FileSystemOperation.java:164)
	at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.runWithinFileSystemLock(FileSystemOperation.java:144)
	at com.ibm.team.filesystem.client.internal.operations.LoadOperation.execute(LoadOperation.java:695)
	at com.ibm.team.filesystem.client.internal.operations.FileSystemOperation.run(FileSystemOperation.java:89)
	at com.ibm.team.build.internal.scm.SourceControlUtility.updateFileCopyArea(SourceControlUtility.java:678)
	at com.ibm.team.build.internal.hjplugin.rtc.RepositoryConnection.checkout(RepositoryConnection.java:429)
	at com.ibm.team.build.internal.hjplugin.rtc.RTCFacade.checkout(RTCFacade.java:410)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at com.ibm.team.build.internal.hjplugin.RTCFacadeFactory$RTCFacadeWrapper.invoke(RTCFacadeFactory.java:96)
	at com.ibm.team.build.internal.hjplugin.RTCCheckoutTask.invoke(RTCCheckoutTask.java:110)
	at com.ibm.team.build.internal.hjplugin.RTCCheckoutTask.invoke(RTCCheckoutTask.java:31)
	at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2387)
	at hudson.remoting.UserRequest.perform(UserRequest.java:118)
	at hudson.remoting.UserRequest.perform(UserRequest.java:48)
	at hudson.remoting.Request$2.run(Request.java:326)
	at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
	at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
	at java.util.concurrent.FutureTask.run(FutureTask.java:138)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
	at java.lang.Thread.run(Thread.java:680)
ERROR: RTC : checkout failure: null

It seems to be very consistent about failing on the third build after wiping the jenkins workspace.

Here is some output from the RTC Log right before one of the failed checkouts:

Dec 13, 2013 3:07:21 AM com.ibm.team.build.internal.hjplugin.RTCScm
FINER: checkout : Build-MacOSX #5 duff Load directory="/space/jenkins/workspace/Build-MacOSX" Build tool="RTC-Build-Toolkit-4.0.4-Installed-Automatically-by-Jenkins" Local Build toolkit="./RTC-buildtoolkit-4.0.4/jazz/buildsystem/buildtoolkit" Node Build toolkit="/space/jenkins/tools/RTC-buildtoolkit-4.0.4/jazz/buildsystem/buildtoolkit/jazz/buildsystem/buildtoolkit" Server URI="https://[redacted]" Userid="[redacted]" Authenticating with c:\[redacted] Build definition="Build-MacOSX" Build workspace="null" useBuildDefinitionInBuild="true" Baseline Set name="Build-MacOSX #5"