Network Cable Unplugged

recently had to replace router, ever since put in new dlink router getting an intermittent error every couple of minutes "local area connection, network cable unplugged" on my desktop connected to port 1 of router.

1. unplugged laptop with wireless card and still get same error, as well tried to remove wireless encryption and still experiencing same error

2. removed router and connected desktop directly to dsl modem and everything is fine.

3. Have been able to determine the following :
this only happens when my VOIP adapter for my IP phone is connected. When I unplug this connection from router trouble disappears ?????
I have moved around between ports on router still experience same problem and always getting this error on desktop that is connected to port 1 of router.

There are no software setting for VOIP adapter and it also works fine when plugged directly into modem.

Any suggestions ?