NUnit error running my c# Selenium WebDriver code
Unzip the driver, and put it in the same folder as where the tests are running from. Add it to the project in Visual Studio, ensuring it's build properties are set to 'Copy always'. This will ensure it is always copied to the same build directory as the compiled .DLL file containing your tests.
You can move it later, but get it working when it is in the same folder as the tests are.