Interface builder not loading in xcode

I am using XC开发者_Python百科ode Version 3.2.6 and iOS SDK 4.3. I created a new view based app (iphone or ipad). After double clicking on the view controller xib and interface builder is not loading up. It seems like it's attempting to open, but nothing.

Have you any thoughts?

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XCode 3.2.6 has separate IB then the SDK. So, you can try to open the file from the interface builder, or if the problem persists, you can even reinstall the XCode. Maybe it is a "built-in" bug, it happened with me too, many times.