You don't say which line your error occurs on, but I'm betting it's either (or both):

                oleadapter.Fill(ds1)

or

                ds.Tables("users").PrimaryKey = New DataColumn() {ds.Tables("users").Columns("user")}

I don't see where you've instantiated either ds or ds1. And, you should be using the same DataSet. You need something like this:

                DataSet ds = New DataSet
                oleadapter.Fill(ds)
                ds.Tables("users").PrimaryKey = New DataColumn() {ds.Tables("users").Columns("user")}

~~Bonnie

>tm = ConfigurationSettings.AppSettings("telemagic" & i.ToString) & "common"
>
>                oleconect.ConnectionString = "data source =" & tm & proveedor
>                olecommand.CommandText = "select user,name from users order by user"
>
>                oleadapter.SelectCommand = olecommand
>                olecommand.Connection = oleconect
>                oleadapter.Fill(ds1)
>                ds.Tables("users").PrimaryKey = New DataColumn() {ds.Tables("users").Columns("user")}