Connection Unavailable - Xcode error after Lion OSX upgrade

I just upgrade to Lion and Xcode 4.1 is giving errors for my old project, al开发者_如何学运维l in Mainmenu.xib:

file:....MainMenu.xib: error: Connection Unavailable: Binding support on Mac OS X versions prior to 10.3 (This nib will be unreadable on such systems)

My target is 10.6 and using 10.6 SDK as well

The funny thing is it still compiles and runs but it is still very annoying to see 9 errors and 37 warnings.

Any suggestions?

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I never found the cure. It only happens in one project, but it all works fine. I submitted a couple of release to the App store already and they are all working fine. I think it is just an harmless but annoying error in the project file.