I'm not sure what this means, as I'm not an EWS expert, I'm afraid - but ePO is flagging these events as WARN not ERROR, so it shouldn't really be causing any problems. Are you seeing any particular issues, or is it just the messages in the log?
there are some other exceptions in this log, whihc I assume not related to the one I described here, these are related to AverAlerts service being unable to do something.
But the WARNings just keep being spawned, which cannot be healthy I suppose. Even if they are warnings. I must be told what they mean to look at them as ignorables.