i get error while i build my solution : i have an architecture i which i have so many layers and project.Generally i get a common error while i build my solution and i really don't get why i am getting this error.i have attached my architecture image and error image.please help me if anyone knows about this error and h[![enter image description here][1]][1]ow to get rid off this error.


[![enter image description here][2]][2]


  [1]: http://i.stack.imgur.com/JIaKw.png
  [2]: http://i.stack.imgur.com/9TiAk.png