I\'m growing thin learving mvc3. I have the following code in my controller
[HttpPost]
public ActionResult Accreditation(Accreditation accreditation)
var fileUpload = Request.Files[0]; is the line where you have your exception, isn't it? You should expect the file to be stored in the property of class Accreditation, not in Request.Files.
So you need properties PressCard and Passport in Accreditation, both of type HttpPostedFileBase, and then use these properties in your code.