title: Build Error - missing required architecture i386 in file
body: <p>I'm getting this error when building my iPhone application:</p>
  
  <blockquote>
    <p>ld: warning: in /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.sdk/System/Library
    /Frameworks/UIKit.framework/UIKit, missing required architecture i386 in file</p>
  </blockquote>
  
  <p>It goes the same for all the frameworks in my app. It's very weird since this was not happening earlier.</p>