ATV with airport express booster

i have two appletvs. the one in the bedroom is in very close proximity to my airport extreme and is always connected to the network and shows up religiously in itunes, regardless of whatever network configuration i setup thru the rest of the house.

i installed an airport express as a network booster in the same room as the appletv in my living room (two floors away from the airport extreme). for whatever reason, that causes huge problems for the downstairs atv. if i umplug the airport express, atv works fine. if i plug it back in, the downstairs atv shows all sorts of connectivity problems (constantly needs reboot, forgets network, downloads at snails pace if at all).

for now i have unplugged my airport express, but i would like to put it back in service for stronger network connections (laptops, iphones, etc.).

any advice, thoughts?

thanks