About the Iphone project:show-location-on-map-using-table

Question

i will take one project source code on to this site and when i run this project on my xcode4.2 then it will give an erro like"Unable to resolve Interface Builder plug-in dependency for "mapViewController.xib". Xcode 4 is missing components necessary to load the following class: IBNSLayoutConstraint. Ensure that Xcode has been properly installed"

so, please give me the solution.

thanks.