When I try to insert a record, I get this error : The underlying provider failed on Open.
This error occurs only with IIS and not with VWD 2008's webserver. 
In the EventViewer I get this Application Error : **Failed to generate a user instance of SQL Server due to a failure in starting the process for the user instance. The connection will be closed. [CLIENT: ]**

```
<add name="ASPNETDBEntities"
     connectionString="
         metadata=res://*/Models.FriendList.csdl|res://*/Models.FriendList.ssdl|res://*/Models.FriendList.msl;
         provider=System.Data.SqlClient;
         provider connection string=&quot;
         Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\ASPNETDB.MDF;
         Integrated Security=True;
         Connect Timeout=30;
         User Instance=True;
         MultipleActiveResultSets=True&quot;"
     providerName="System.Data.EntityClient" />

```

**I am using aspnetdb.mdf file, and not any external database.**
I have searched enough for this, but no use.

**Everything works fine with VWD webserver**