Navigate between UiNavigation Controller and Uitabbar Controller in iOS 4.3

Question

In my app,I'm able to navigate the controllers from a uinavigation controller to a tabbar item's navigation controller(Inside my tabbar controller each tabbar item has seperate uinavigation controller) but back to navigation controller is not working.

I tried both pushviewcontroller and presentModalViewController but in both cases the back navigation is not working.

This problem occurs only in iOS 4.3 but works fine in iOS 5

I tried the below code to dismiss the modalviewController:

 [self  dismissModalViewControllerAnimated:YES];