title: Unity 3: The type does not have an accessible constructor
body: <p>I have a following interface and implementation</p>
  
  <pre><code>namespace ProjectName.Web
  {
      public interface IWebUtil
      {        
      }
  }
  
  
  namespace ProjectName.Web
  {
      public class WebUtil : IWebUtil
      {                
      }
  }
  </code></pre>
  
  <p>in my config i have this registration. I am using Unity 3.</p>
  
  <pre><code>&lt;unity xmlns="http://schemas.microsoft.com/practices/2010/unity"&gt;
    &lt;assembly name="ProjectName.Web" /&gt;
    ...
     &lt;register name="WebUtil" type="ProjectName.Web.IWebUtil" mapTo="ProjectName.Web.WebUtil"&gt;
       &lt;lifetime type="transient" /&gt;    
     &lt;/register&gt;
    ...
  </code></pre>
  
  <p>When I try to resolve this configuration I am getting this error:</p>
  
  <pre><code>Exception is: InvalidOperationException - The type IWebUtil does not have an accessible       constructor.
  -----------------------------------------------
  At the time of the exception, the container was:
  Resolving ProjectName.Web.IWebUtil,(none)
  </code></pre>
  
  <p>I have tried to add empty public constructor but no sucess. </p>
  
  <p>Can anybody help with this? thanks.</p>