DotNet Portal Development Kit - Problem connecting to SQL Server

Any help would be appreciated. I'm trying to create a portal application with the dotnet pdk. I need to connect to a SQL Server database.

When I run the application in the portal I'm getting the following error:

Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[SqlException: Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection.]

System.Data.SqlClient.ConnectionPool.CreateConnection() +402

System.Data.SqlClient.ConnectionPool.UserCreateRequest() +147

System.Data.SqlClient.ConnectionPool.GetConnection(Boolean& isInTransaction) +391

System.Data.SqlClient.SqlConnectionPoolManager.GetPooledConnection(SqlConnectionString options, Boolean& isInTransaction) +311

System.Data.SqlClient.SqlConnection.Open() +384

System.Data.Common.DbDataAdapter.QuietOpen(IDbConnection connection, ConnectionState& originalState) +44

System.Data.Common.DbDataAdapter.FillFromCommand(Object data, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +304

System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +77

System.Data.Common.DbDataAdapter.Fill(DataSet dataSet) +38

PortalApplication2.PortalComponent1.Page_Load(Object sender, EventArgs e)

System.Web.UI.Control.OnLoad(EventArgs e) +55

SAP.Portal.Web.UI.PortalComponent.OnLoad(EventArgs e) +17

System.Web.UI.Control.LoadRecursive() +27

System.Web.UI.Control.LoadRecursive() +90

System.Web.UI.Control.LoadRecursive() +90

System.Web.UI.Page.ProcessRequestMain() +750