UISplitViewController appears as unresolved

Hi
I tried creating a project using the Split View based application. Most of the code appears fine except for certain classes and properties that show up as red / unresolved.

Some of them are

UIPopoverControllerDelegate, UISplitViewControllerDelegate, UISplitViewController, UIPopoverController dismissPopoverAnimated,   contentSizeForViewInPopover

The project does compile and run without errors. Any idea why the above are showing as unresolved?

Using XCode Version 3.2.4 (1708).

Thanks,
Sanjiv