MSUnit Assert not Working

Everything is working on MSUnit except my Assert, I checked and found that it's a bit different in MSUnit than nUnit, went through a blog post and doing exactly same but still getting error while debugging the test.

When I check my ex in the Unit Test (after throwing the error), the message I get is "error in the application", which fails the test as the expected message is different

Any Ideas?

[TestMethod]
    [ExpectedException(typeof(InvalidAreaException))]
    public void GetAreaWithNegativeValueTest()
    {
        try
        {
            Utility.GetArea(2, -1, 2);

        }
        catch (InvalidAreaException ex)
        {
            Assert.AreEqual ("Inputs must be positive numbers", ex.Message);
            throw;
        }
    }

//Exception Class   
        public class InvalidAreaException : ApplicationException, ISerializable
    {
    public  string msg;

    public InvalidAreaException(string message)
    {
        //msg = message;
    }
 }

//Actual Method to be tested
public static double GetArea(int arg1, int arg2, int arg3)

    {
        double area = 0d;

        if ((arg1 < 0) || (arg2 < 0) || (arg3 < 0))
        {
            throw new InvalidAreaException("Inputs must be positive numbers");
        }   
    }