org.apache.lucene.store.AlreadyClosedException: this ReferenceManager is closed

What does this error mean

I have to reboot entire vm to get it to clear...can't just restart the application..

it has started happening multiple times a day

I get this error

Type:
Value: org.apache.lucene.store.AlreadyClosedException: this ReferenceManager is closed

Traceback (most recent call last):
File "/opt/zenoss/lib/python2.7/site-packages/ZPublisher/Publish.py", line 126, in publish
request, bind=1)
File "/opt/zenoss/lib/python2.7/site-packages/ZPublisher/mapply.py", line 77, in mapply
if debug is not None: return debug(object,args,context)
File "/opt/zenoss/lib/python2.7/site-packages/ZPublisher/Publish.py", line 46, in call_object
result=apply(object,args) # Type s to step into published object.
File "/opt/zenoss/lib/python2.7/site-packages/Products/Five/browser/pagetemplatefile.py", line 125, in __call__
return self.im_func(im_self, *args, **kw)
File "/opt/zenoss/Products/ZenWidgets/FileGzipper.py", line 82, in __call__
return original(self, __instance, *args, **keywords)
File "/opt/zenoss/lib/python2.7/site-packages/Products/Five/browser/pagetemplatefile.py", line 59, in __call__
sourceAnnotations=getattr(debug_flags, 'sourceAnnotations', 0),
File "/opt/zenoss/lib/python2.7/site-packages/zope/pagetemplate/pagetemplate.py", line 113, in pt_render
strictinsert=0, sourceAnnotations=sourceAnnotations)()
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 271, in __call__
self.interpret(self.program)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 343, in interpret
handlers[opcode](self, args)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 888, in do_useMacro
self.interpret(macro)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 343, in interpret
handlers[opcode](self, args)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
self.do_optTag(stuff)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
return self.no_tag(start, program)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 513, in no_tag
self.interpret(program)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 343, in interpret
handlers[opcode](self, args)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 946, in do_defineSlot
self.interpret(slot)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 343, in interpret
handlers[opcode](self, args)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 533, in do_optTag_tal
self.do_optTag(stuff)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 518, in do_optTag
return self.no_tag(start, program)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 513, in no_tag
self.interpret(program)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 343, in interpret
handlers[opcode](self, args)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tal/talinterpreter.py", line 620, in do_insertText_tal
text = self.engine.evaluateText(stuff[0])
File "/opt/zenoss/lib/python2.7/site-packages/Products/PageTemplates/Expressions.py", line 225, in evaluateText
text = self.evaluate(expr)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tales/tales.py", line 696, in evaluate
return expression(self)
File "/opt/zenoss/lib/python2.7/site-packages/zope/tales/expressions.py", line 217, in __call__
return self._eval(econtext)
File "/opt/zenoss/lib/python2.7/site-packages/Products/PageTemplates/Expressions.py", line 155, in _eval
return render(ob, econtext.vars)
File "/opt/zenoss/lib/python2.7/site-packages/Products/PageTemplates/Expressions.py", line 117, in render
ob = ob()
File "/opt/zenoss/Products/ZenUI3/browser/pages.py", line 75, in getInfoObject
and not callable(getattr(info, key)))
File "/opt/zenoss/Products/Zuul/infos/__init__.py", line 130, in severity
self.setWorstEventSeverity(zep.getWorstSeverityByUuid(self.uuid))
File "/opt/zenoss/Products/Zuul/facades/zepfacade.py", line 616, in getWorstSeverityByUuid
return self.getWorstSeverity([tagUuid], default=default, ignore=ignore)[tagUuid]
File "/opt/zenoss/Products/Zuul/facades/zepfacade.py", line 635, in getWorstSeverity
eventTagSeverities = self._getEventTagSeverities(tags=tagUuids)
File "/opt/zenoss/Products/Zuul/facades/zepfacade.py", line 710, in _getEventTagSeverities
response, content = self.client.getEventTagSeverities(from_dict(EventFilter, eventFilter))
File "/opt/zenoss/lib/python2.7/site-packages/zenoss/protocols/services/zep.py", line 189, in getEventTagSeverities
return self.client.post('tag_severities', body=event_filter)
File "/opt/zenoss/lib/python2.7/site-packages/zenoss/protocols/services/__init__.py", line 174, in post
return self._request_with_body(path, method='POST', body=body, params=params, headers=headers)
File "/opt/zenoss/lib/python2.7/site-packages/zenoss/protocols/services/__init__.py", line 169, in _request_with_body
response, content = self._executeRequest(request)
File "/opt/zenoss/lib/python2.7/site-packages/zenoss/protocols/services/__init__.py", line 153, in _executeRequest
raise ServiceResponseError(response.reason, response.status, request, response, content)
ServiceResponseError: org.apache.lucene.store.AlreadyClosedException: this ReferenceManager is closed