Q: Connections..Wifi/Ethernet

So, in order to stream effectively, I have had to connect AppleTV via ethernet, but now, I can't play items selected within Appletv, from 'Computers' as they are connected via WIFi. Seemingly, my ethernet and wifi connectins are different - despite being via the same router, in the same room, practically on top of the Appletv box..

VERY frustrated that I can easily stream anything on my iPad via WiFi, but Apple TV has enough problems to make me hardwire it to the router!

I am assuming I am doing something wrong?

any help would be greatly appreciated