Network message when printer is turned on

Hey there,

I have a network hooked up between two computers in my
house, and a laser printer is hooked up to mine. Every
time I turn on my printer, the LAN connection drops off
and it says "A Network Cable is Unplugged". This goes on
until the printer warms up, then it goes away. But I
just came back into the room after the printer's been on
for a few minutes, and the message is back up again.

When I turn off the printer, it goes away/

Does anyone know what is causing this, and how I can fix
it???

Thanks!

Will