I think the problem is with the SQLDataSource. To see the reccomended way of connecting to the database see:

http://www.adefwebserver.com/DotNetNukeHELP/DNN_ShowMeThePages/

Dim mySqlString As New StringBuilder()
mySqlString.Append("SELECT FriendlyName, Description ")
mySqlString.Append("FROM {databaseOwner}{objectQualifier}DesktopModules ")
mySqlString.Append("WHERE Description like '%' + @SearchString + '%' ")
mySqlString.Append("ORDER BY FriendlyName")
Dim myParam As SqlParameter = New SqlParameter("@SearchString", SqlDbType.VarChar, 150)
myParam.Value = SearchString
Me.GridView1.DataSource = CType(DataProvider.Instance().ExecuteSQL(mySqlString.ToString(), myParam), IDataReader)
Me.GridView1.DataBind()

The script commands "{databaseOwner}" and "{objectQualifier}" indicate that they are to be replaced by configuration settings in the web.config file. Normally "{databaseOwner}" is set to ".dbo" and  "{objectQualifier}" is set to nothing (it would not have a setting). However, if alternate settings were indicated in the web.config file, those settings would be inserted into the script.