UIButton, created by Interface Builder, is crashing-Collection of common programming errors

I have narrowed down an ugly bug, but since it seems like something internal to the nib/Interface Builder, I’m at a loss of what to do next.

I’ve got a UIView created in IB which functions as a custom dialog box. It shows a message and two buttons. (Proceed or Cancel.) Both buttons have a Background image set in Interface Builder.

Something is wrong with the way the background image for the cancel button is being handled. With NSZombieEnabled, I’ve been running the program. Most often, the method below logs this:

-[ModalDialog showInView:title:message:cancelText:proceedText:]
dialogProceedButton