I have a Quipp400W. This is a new stacker for us. We usually use a 500, but this one came with the SLS1000 we just had installed. I have been continuously getting alerts of "End of zone" and "last paper time out". This stacker is not tied into the computer so this should not happen. In a 10,000 unit run, it happened 15 times. Anybody else experience this? What was the solution to get it to go away?