Strange etrace

I was running my data analysis program (Reads a file, processes 
the data and writes a file. No promises, single vat, single 
turn.) and I received the following etrace:

=== 2011-01-31T07:18:11.651Z 
(PendingEvent.report:PendingEvent.java:107) WRN
causality: Problem in turn <<Vat start in <runs in start>>,3>:
--vvvv--
Failed: OldFarRef may only be smashed: <Far ref>

- DelayedRedirector#run(Object)
. <a DelayedRedirector>(<Far ref>)

java.lang.RuntimeException: Failed: OldFarRef may only be 
smashed: <Far ref>
     at org.erights.e.develop.assertion.T.fail(T.java:85)
     at org.erights.e.elib.ref.OldFarRef.setTarget(OldFarRef.java:105)
     at org.erights.e.elib.ref.EProxyResolver.resolve(EProxyResolver.java:189)
     at org.erights.e.elib.ref.EProxyResolver.resolve(EProxyResolver.java:201)
     at org.erights.e.elib.ref.DelayedRedirector.run(DelayedRedirector.java:82)
     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 org.erights.e.elib.prim.InstanceMethodNode.innerExecute(InstanceMethodNode.java:111)
     at org.erights.e.elib.prim.JavaMemberNode.execute(JavaMemberNode.java:187)
     at org.erights.e.elib.prim.E.callAll(E.java:164)
     at org.erights.e.elib.vat.PendingDelivery.innerRun(PendingDelivery.java:96)
     at org.erights.e.elib.vat.PendingEvent.run(PendingEvent.java:74)
     at org.erights.e.elib.vat.HeadlessRunner.run(HeadlessRunner.java:174)
     at java.lang.Thread.run(Thread.java:680)

--^^^^--

I re-ran what I think is the same program with the same data and 
didn't get an etrace. (I have run many versions of the program 
and only gotten etraces with various thrown exceptions, except 
for this time)

Any idea what this means?

Cheers - Bill

-----------------------------------------------------------------------
Bill Frantz        | I like the farmers' market   | Periwinkle
(408)356-8506      | because I can get fruits and | 16345 
Englewood Ave
www.pwpconsult.com | vegetables without stickers. | Los Gatos, 
CA 95032