UIAlert View not popping up in Navigation-based App

[appcody]

I've been working on a project and need an alert view to pop up when i click on a button. This is really simple to do, because i've already done it in a View-based application. I copied and pasted the same code into my navigation-based application, but everytime i click the button with the UIAlert View the application crashes. I checked on the Interface builder and nothing seems to be wrong... any help? Thanks in advance,