SPSite: FileNotFoundException was unhandled

I create a console project in Visual Studio 2010.

After adding a reference to Miscrosoft.SharePoint, I add following code in the project:

When it opens a SPSite, FileNotFoundException is thrown as below:

Since the console project set the Platfrom target is X86 as default and I run the project under X64 environment. Therefore, I need to update the Platform target to x64.

1. Right click the project

2. Click Properties

3. Click Build and update the value in Platfrom target