missing system.data.entity.migrations
===

I'm trying to enable migrations.  It couldn't find my dbcontext when I called Enable-Migrations from the package manager console, but once I referenced the namespace correctly, I can add it into my configuration.cs file.  The problem is that near the top in my using statements (generated automatically by the Enable-Migrations command), it says: 

using System.Data.Entity.Migrations;
and Migrations has a squiggly line underneath.  

And therefore, the DBMigrationsConfiguration command won't work and the Build fails.  

I'm using VS 2010 Premium, and I checked Nuget and I'm using EntityFramework 4.3.1  I've had no problems using EF with this web app to date, but want to set up code first migrations.  

I also checked for updates to the EntityFramework in nuget but it said none were available. When I try to add the reference, I can't find it in the .NET components.  I'm set to .NET 4.0, is that the problem?  



