I have followed installation steps from the core plot in Application url.
As defined in subject, core plot version is 1.0 which was tried with iPhone 5.0 Simulator in Xcode 4.2.
I was also getting the similar error but on adding only the CorePlotHeaders folder to my xcode project solved the problem. Earlier I had the entire framework which I had downloaded in the project and it gave me that error.
Now it works!