Ok, tried the exact same thing in my project: failed - same results where it exits the app. Made a copy of your app, left your XNA the same, brought my assets in...same failure as before.
I'm almost convinced it is Win 8.
I'm going to try on Win 7 and see if that fixes it. The only reason I hadn't been developing on Win 7 is for some reason the Zune software refuses to sync to my phone on Win 7 but will on my Win 8 machine. I may just have to jump through a couple hoops.
I'll let you know what happens.