XCode Back Button leads to blank screen? HELP!??!

Thanks for looking. I'm creating a basic app with a friend, we've got no storyboard and no ARC. i have made next buttons to the next .xib fine, and made back buttons too. all work well except the button from the 2nd .xib back to the very first .xib.

i have no coding issues or warnings and when running a simulator all the buttons work. just need to get rid of the black blank screen. it should show a text view with title bar and toolbar with a next button on. but its just blank and black.!! so frustrating.

I am very new to coding etc and have been following tutorials on you tube.

i have a basic understanding but have seen so many different ways to solve very similar problems.

Thanks again for looking

Craig