Just an update on this. Learned alot from some very helpful people who engineer networking gear for a living. For those reading this in the future, you should never ever have anything but ZERO errors on your WAN packet statistics with any router. It will be a hardware issue assuming the unit previously did not exhibit the errors. A problem either with the cable (either defective or noise), the modem, or the router itself. A WAN not to be confused with wireless LAN (WLAN) which does have packet errors as a normal occurance with todays technology.
So I tried three different Cat6 (in case it was noise) patch cables between the modem and router WAN ports without change. I took the router to someone elses house and dropped it in their network and the problem persisted which eliminated my cable modem. That left the problem squarely with the DGL-4100.
Since the unit is still under warranty pursuing an RMA now.