title: Could not load file or assembly Microsoft.Practices.EnterpriseLibrary.Common, Version=4.1.0.0 ASP.NET 4.0
body: <p>Platform : ASP.NET 4.0<br>
  Application : A website project with a Datalib ClassLibrary attached to it<br>
  Dependencies:<br>
  <img src="https://i.stack.imgur.com/9wvU9.png" alt="Dependencies of the project">
  IIS: 5.1(local and IIS 7.0 online)  </p>
  
  <p>I am getting the error at localhost. I haven't checked online yet.<br>
  The whole thing was working at ASP.NET 3.5 and now when i upgraded to ASP.NET 4.0 I get the following error.  </p>
  
  <p><img src="https://i.stack.imgur.com/XGzU4.png" alt="The yellow screen at Browser"></p>
  
  <p>The Stack Trace is</p>
  
  <p><img src="https://i.stack.imgur.com/td5Kc.png" alt="alt text"></p>
  
  <p>At VisualStudio 2010, the error is</p>
  
  <p><img src="https://i.stack.imgur.com/jsP8X.png" alt="alt text"></p>
  
  <p>This is not happening everytime.<br>
  The first runs always show this error.  </p>
  
  <p>What could be wrong?</p>