Need help with speaker selector+amplifier (In-Ceiling Speaker setup)

Hello all. Best place I could think of to post this in. I bought a new home that came with a home sound system.

The general bullet points.
-Have a total of 9 speakers. 2 pair in Kitchen, 2 pair in LivingRoom, 2 pair in Dining Room, 2 pair on patio outside, 1 single in master bathroom. Each room has their respected volume switch.
-All 9 speakers connect to a Niles SS-6 speaker selection unit. Protection was ON.
-Niles connects to an Integra adm 20.4 Amp.
-I use the Amps RCA audio in to connect it to my Apple express base station for AirPlay support.

Now the issue. Yesterday I played a song and turned on all speakers on the Niles box when the AMP decided to kick it 2 seconds in. Now the amp won't power on after pressing the power button. It makes a double click sound when I try to power it on. This system came with the house thus I assume it worked fine while the previous owners were living there.

Any ideas why the AMP would have kicked it? I want to purchase the same model as before but am afraid a similar thing will happen if I play all the speakers at once.

Thanks for your help