A Zenoss error has occurred

A Zenoss error has occurred, what can I do to fix the problem Appreciated..

Type:
Value: NULL object passed to Py_BuildValue

Traceback (most recent call last):
File "/opt/zenoss/lib/python/ZPublisher/Publish.py", line 134, in publish
transactions_manager.commit()
File "/opt/zenoss/lib/python/Zope2/App/startup.py", line 301, in commit
transaction.commit()
File "/opt/zenoss/lib/python/transaction/_manager.py", line 89, in commit
return self.get().commit()
File "/opt/zenoss/lib/python/transaction/_transaction.py", line 342, in commit
reraise(t, v, tb)
File "/opt/zenoss/lib/python/transaction/_transaction.py", line 333, in commit
self._commitResources()
File "/opt/zenoss/lib/python/transaction/_transaction.py", line 473, in _commitResources
reraise(t, v, tb)
File "/opt/zenoss/lib/python/transaction/_transaction.py", line 447, in _commitResources
rm.commit(self)
File "/opt/zenoss/lib/python/ZODB/Connection.py", line 567, in commit
self._commit(transaction)
File "/opt/zenoss/lib/python/ZODB/Connection.py", line 623, in _commit
self._store_objects(ObjectWriter(obj), transaction)
File "/opt/zenoss/lib/python/ZODB/Connection.py", line 658, in _store_objects
p = writer.serialize(obj) # This calls __getstate__ of obj
File "/opt/zenoss/lib/python/ZODB/serialize.py", line 422, in serialize
return self._dump(meta, obj.__getstate__())
SystemError: NULL object passed to Py_BuildValue