Universal App won't run on iPad Simulator

Question

I have an existing iPhone app that I'm trying to convert into a universal app for both iPhone and iPad. Everything seems to work fine when I run it on an iPad device, but I get the following runtime error when I try to run in the iPad simulator:

dyld: Symbol not found: _CFXMLNodeGetInfoPtr
  Referenced from: /System/Library/Frameworks/Security.framework/Versions/A/Security
  Expected in: /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.2.sdk/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation
 in /System/Library/Frameworks/Security.framework/Versions/A/Security

I am building using the latest 4.1 SDK. My project settings are set to build for iPhone/iPad. My deployment target is set to iOS 3.1. I have weakly linked to UIKit.framework.

Any help would be appreciated. Thanks!