SQL Network Interfaces, error: 26, but not connection string?

Having used Winhost successfully before, I'm a bit stymied by a weird issue with my latest site.

I'm using MVC3 .NET/EF4.1, and SQL Server 2008 R2 (not SQLEXPRESS.) More extensive details on my issue will be found here: http://stackoverflow.com/questions/...but-not-connection-string-is-it-entity-framew

My site comes up, no errors; I can login, no errors. But when I try to go to other pages after that, I get the SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified (which usually means a bad connection string.)

Only, the thing is, I'm pretty sure since I'm able to login that it's not the connection string. (Note: the aspnet_membership etc. tables are included in my database, and everything works without errors in my local environment.)

Here is my connection string with the site name and password made anonymous.

<add name="ApplicationServices" connectionString="Data Source=tcp:s07.Winhost.com;Initial Catalog=DB_39855_mysite;User ID=DB_39855_mysite_user;Password=********;Integrated Security=False;" providerName="System.Data.SqlClient" />

Thanks to anyone who has even a wild guess at helping me.

 

I think that I've got this figured out, and hopefully this will help anyone in the same situation.

What I think happened is that the EF4.1 put in place an Entities item that is referenced in Web.config, which has a connection string of its own. Of course, I already had a connection string. The issue was that the different parts of the app were using the different connection strings. So, the security/login was using a good connection string, whereas the various custom pages were trying to use the Entities connection string (and failing, since the un-changed connection string for Entities was pointing at somewhere on my local drive.)

I did the old brute force method of setting up a new (empty) project and adding singular pieces until something broke. It was the Entities (or lack thereof) that broke the app in this context, which got me to look at it more closely.