AE and ZTE ZXV10 W300 Series not working

I have my brand new AE and a ZTE ZXV10 W300 Series Router. The router is the one who connects to the internet and shares it. When I configure my AE to connect to my wireless network (i want to use mainly Airplay) after 15 minutes logs out, and needs to reboot to work again. I tried all posible configirations and Airplay keeps failing. Now i configured the AE as a new network and i connect my Imac through my wireless connection so i can use airplay, and through the ethernet to my ZTE router for the internet. Now Airplay works flawless, but its not the idea to have 2 connections when I could do all through my wireless connection.

Any Ideas?
Please Help