The client was unable to establish a connection because of an error during connection initialization process before login. Possible causes include the following: the client tried to connect to an unsupported version of SQL Server; the server was too busy to accept new connections; or there was a resource limitation (insufficient memory or maximum allowed connections) on the server. (provider: Named Pipes Provider, error: 0 - No process is on the other end of the pipe.)
Security Changes in the .NET Framework 4
http://msdn.microsoft.com/en-us/library/dd233103.aspx