I did a couple of things and the problem has stopped for now.
I turned multithreading off in VEP and it made no difference.
I had a printer plugged into the second ethernet port of my slave. I pulled it out.
I restarted the computer.
Problem has stopped.
I turned multithreading back on to 8 in VEP.
Problem still won't happen.
Could the printer or even using the second ethernet port have caused the problem? I needed this plugged in before I bought the gigabit switch because I had run out of sockets on the Airport Extreme.
Now I can plug it into the Switch.
I have reconnected the printer and still the problem won't happen.
It WAS happening every 3 or 4 minutes before.
Got me beat. I'm not sure if it was turning off and on the multithreading in VEP or restarting the computer or unplugging the printer and freeing up an ethernet port.
It was doing this yesterday so I guess that rules out restarting the computer because it was re started this morning.
It could also be that toggling multithreading in VEP is the solution.