That is a 7.1 receiver...are you using a 5.1 setup by any chance?
With my Yamaha when I first got it, I put the rear speakers in the surround back ports on the back of the receiver. Every time I turned the volume up, it would go into protection mode and shut down. Called Yamaha and for 5.1 setup on a 7.1 or 7.2 receiver (at least the Yamaha anyway), the rear speakers should be connected to the surround ports on the back of the receiver, not the surround back ports.
Klipsch RF-52 II // RC-52 II // RS-42 II
Klipsch KG 2.5