"Unable to read the project fileA close inspection revealed that the CUDA build tools were still referring to the old CUDA v 5.5 sdk build tools. Since I had already uninstalled the previous CUDA version, the system could not find the path.
. The imported project was not found file cannot be found...."
You just have to update the CUDAPropsPath environment variable to point to the new SDK MSBuildExtensions folder. Doing so loads all of the sample projects fine.
Hope this tip will help others as well.