Getting database connection error in three tier architechture in mvc 3

I'm trying to implement basic three tier architecture with mvc 3. but getting an error while running the solution ( showing no error while building the solution). The organization of my projects & error message can be seen in the attached image. enter image description here

Please help.

OK guys, This is an update for.

As specified by some comments, I copied the original connection string from app.config to my web.config file & getting this error as shown in the image. enter image description here

I tried to search a lot but no clue! Any help will be highly appropriated.

Solution

@Maarten is right. you always copied the normal connection string (that is a part of entity-connection string). you need to copy the entire connection string that was generated in your App.config file in Data layer and paste it in the web.config file in your presentation layer. the entity-connection string like as :

<add name="NorthwindEntities" connectionString="metadata=res://*/Model1.csdl|res://*/Model1.ssdl|res://*/Model1.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.\sqlexpress;initial catalog=Northwind;persist security info=True;user id=sa;password=Blister01;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />

don't copy-paste it, it is just a sample