Sorry for the trouble you are having.
The easiest thing to do is overwrite the XNAPerformanceChecker.csproj from the cd with this file. Then double click on it and compile it. The original file that was included was for the CTP version instead of the final release version.
The downloaded file should simply replace the other file that already exists. Then double clicking on the .csproj file should open it up inside of Visual Studio / Visual C# Express. The .sln (solution) file will also load up the project just fine.
Once it is loaded you can hit CTRL+F5 to build it or just hit F5 (or hit the play button) to compile and run the code.
Hope this helps, but if not please let me know and I'll try to do better at explaining it.