I am trying to build a selenium-silverlight UI test using selenium Nuint test framework. Here is my code
using System;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.IE;
using OpenQA.Selenium.Support.UI;
using System.Text;
using OpenQA.Selenium.Interactions;
using System.Configuration;
using System.Threading;
using Selenium;
using ThoughtWorks.Selenium.Silvernium;
using DBServer.Selenium.Silvernium.Fixtures;
using NUnit.Framework;
namespace Rahul_Test
{
[TestFixture]
public class UnitTest1
{
    protected static IWebDriver driver;
    protected WebDriverWait wait;
    protected StringBuilder verificationErrors;
    private string baseURL;
    protected static Actions builder;
    protected Silvernium silvernium;
    protected ISelenium selenium;
    protected ICommandProcessor processor;
    //initial setup
    [SetUp]
    public void SetupTest()
    {
        selenium = new DefaultSelenium("localhost", 4444, "*firefox", "http://www.google.com");
        selenium.Start();
        selenium.Open("http://atlas/Dev/Axioma/");
        silvernium = new Silvernium(selenium, "InteractiveElement");  //this line throws error at runtime/while running tests in debug mode...
        //Note: Build does not throw any errors on compilation
    }
    //open browser test case
    [Test]
    public void Login()
    {
        NUnit.Framework.Assert.IsFalse(false);
    }
}
Project/Solution builds without any errors but when I debug/run the test case from test it fails with following error.
Test Name: Login
Test FullName: Rahul_Test.UnitTest1.Login
Test Source: c:\Users\rlodha\Documents\Visual Studio 2012\Projects\SampleUITest\SampleUITest\UnitTest1.cs : line 58
Test Outcome: Failed
Test Duration: 0:00:00.205
Result Message: SetUp : System.IO.FileNotFoundException : Could not load file or assembly 'Silvernium, Version=1.0.4254.29979, Culture=neutral, PublicKeyToken=null' or one of its dependencies.
The system cannot find the file specified. Result StackTrace: at Rahul_Test.UnitTest1.SetupTest()
I can't figure out why it is able to compile with Silvernium Assembly reference added but not able to load Silvernium assembly at run/debug time.
Code for MSTest
using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using OpenQA.Selenium;
using OpenQA.Selenium.Chrome;
using OpenQA.Selenium.IE;
using OpenQA.Selenium.Firefox;
using OpenQA.Selenium.Support.UI;
using System.Text;
using OpenQA.Selenium.Interactions;
using System.Configuration;
using System.Threading;
using Selenium;
using ThoughtWorks.Selenium.Silvernium;
//using NUnit.Framework;
namespace Rahul_Test
{
    [TestClass]
    public class UnitTest1
    {
        //copy this part for defining a class for IE and chrome
        protected static IWebDriver driver;
        protected WebDriverWait wait;
        protected StringBuilder verificationErrors;
        private string baseURL;
        protected static Actions builder;
        protected Silvernium silvernium;
        protected ISelenium selenium;
        //protected ICommandProcessor processor;
        //initial setup
        [TestInitialize]
        public void SetupTest()
        {
            if (driver == null)
            {
                driver = new FirefoxDriver();
                driver.Manage().Window.Maximize();
                baseURL = "";
                verificationErrors = new StringBuilder();
                driver.Navigate().GoToUrl("http://atlas/Dev/Axioma/");
                builder = new Actions(driver);
                //processor=new 
                selenium = new DefaultSelenium("localhost", 4444, "*firefox", "http://www.google.com");
                //selenium.Start();
                //selenium.Open("http://atlas/Dev/Axioma/");
                silvernium = new Silvernium(selenium, "InteractiveElement");
                //var silverlightapp = new SilverlightApplicationFixture("localhost", 4444, "*firefox", "http://www.google.com");
                // }
                //wait = new WebDriverWait(driver, TimeSpan.FromSeconds(35));
                //wait = new WebDriverWait(driver, TimeSpan.FromSeconds(Convert.ToInt16(ConfigurationManager.AppSettings["TimeOut"])));
            }
        }
        //open browser test case
        [TestMethod]
        public void Login()
        {
            Assert.IsFalse(false);
        }
    }
}
And Error Log for MSTest
Test Name:Login
Test FullName:Rahul_Test.UnitTest1.Login
Test Source:c:\Users\rlodha\Documents\Visual Studio 2012\Projects\SampleUITest\SampleUITest\UnitTest1.cs : line 57
Test Outcome:Failed
Test Duration:3.36805555555556E-06
Result Message:
Initialization method Rahul_Test.UnitTest1.SetupTest threw exception. System.IO.FileNotFoundException: System.IO.FileNotFoundException: Could not load file or assembly 
'Silvernium, Version=1.0.4254.29979, Culture=neutral, PublicKeyToken=null' or one of its dependencies. 
The system cannot find the file specified.Assembly manager loaded from:  C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll
Running under executable  C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO 11.0\COMMON7\IDE\COMMONEXTENSIONS\MICROSOFT\TESTWINDOW\vstest.executionengine.exe.config
=== Pre-bind state information ===
LOG: DisplayName = Silvernium, Version=1.0.4254.29979, Culture=neutral, PublicKeyToken=null
 (Fully-specified)
LOG: Appbase = file:///C:/Users/rlodha/Documents/Visual Studio 2012/Projects/SampleUITest/SampleUITest/bin/Debug
LOG: Initial PrivatePath = NULL
Calling assembly : SampleUITest, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null.
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO 11.0\COMMON7\IDE\COMMONEXTENSIONS\MICROSOFT\TESTWINDOW\vstest.executionengine.exe.Config
LOG: Using host configuration file: 
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: The same bind was seen before, and was failed with hr = 0x80070002.
.
Result StackTrace:at Rahul_Test.UnitTest1.SetupTest()