If your are having a problem with "DbContext" class in Entity coding.
Please download the dll from http://packages.nuget.org/v1/package/download/entityframework/4.3.0
and remane  "EntityFramework.4.3.0.nupkg" to "EntityFramework.4.3.0.nupkg.rar".
Add the dll reference into your project and go on .

thanks