Pioneer AV Receiver Protection Mode

Just installed a new in wall speaker system with a Pioneer VSX-520-k and have been thrilled with the sound quality thus far.

The problem I am running into is when I watch blu ray movies such as the recent Star Trek. I set the receiver to auto surround to detect the codec, but what happens is that the receiver will turn itself off (protection mode) when a loud sound effect (explosion or loud clang of metal) happens. quiet scenes at high volume are fine, but the action sequences seem to do something to the receiver to make it give up the ghost.

I have confirmed that one of the speakers is bad, and have disconnected it (but still have the same problem). I am going to try putting the receiver in 5 channel stereo to see if I can replicate the problem, but I am honesty baffled by this one.

let me include some additional information:

all 5 in wall speakers are rated at 8 ohms, 50watt minimal 100W maximum. I am not currently using a subwoofer. my receiver is rated at 550 total watts at 110W per channel.

I would have wanted to use 16 gauge speaker wire, but I already had 18 gauge wire pre run through the walls.

well my family accidently threw away the microphone for calibration. I did, however, lower the Db level per channel from 0 Db down to -8 Db, which seemed to fix the problem. I was able to play movies at a very high volume level without any problem. i think the issue is fixed now.