Getting error when trying to programmatically switch views?

I declared my view in my .h with:

IBOutlet UIViewController *flightdataview;

@property (nonatomic,retain) IBOutletUIViewController *flightdataview;

and I'm trying to switch views using this code:

[selfpresentModalViewController:flightdataviewanimated:YES];

However I get this when I try to switch views:

'Application tried to present a nil modal view controller on target <FlightTrackControler: 0xa162770>.'

Any ideas?

Thanks.