Project file can't be build error you don't have permission to view it
I have resolve the issue by following way. The project i have download from the internet don't have the executable file in info.plist which should be there and its value should be this ${EXECUTABLE_NAME}. Instead of this value it consist some different value. So i have changed it ${EXECUTABLE_NAME} this value then clean->build->run successfully.

See the below link also 

https://stackoverflow.com/questions/27355361/error-while-build-project-xcode-says-you-dont-have-permission#