ho provato un po' ma non trovo problemi :master:
vedi se può servire.
codice:
Option Strict On

Partial Class prove_a
    Inherits System.Web.UI.Page

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim vista As String = "REPORT_5"
        Dim con As OleDbConnection = Nothing

        Try
            'creo nuova connessione
            con = New OleDbConnection(StringaConnessione)
            con.Open() 'la apro

            'se la query non esiste la creo
            If Not ExistReport(con, vista) Then
                Dim command As OleDbCommand = con.CreateCommand()

                command.CommandText = "create view " & vista & " as select distinct id_comune, nome_comune from comuni where codice_istat_regione = '20'"
                command.ExecuteNonQuery()
            End If

            'popolo il GridView
            'la procedura utilizza un OleDbDataReader
            libreria.DataBind(Me.GridView1, con, "SELECT * FROM REPORT_5", Nothing)

        Catch ex As Exception
            'se errore stampo messaggio a video
            PrintLn(ex.Message)

            'svuoto la griglia
            Me.GridView1.DataSource = Nothing
            Me.GridView1.DataBind()

        Finally
            'sempre e comunque chiudo la connessione
            If con IsNot Nothing Then con.Close()
        End Try
    End Sub

    'restituisco una tabella con le query
    Private Function GetTables(ByVal conn As OleDbConnection) As DataTable
        Return conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, New Object() {Nothing, Nothing, Nothing, "VIEW"})
    End Function

    'dà vero o falso se la query esiste già
    Private Function ExistReport(ByVal con As OleDbConnection, ByVal report As String) As Boolean
        Dim dt As DataTable = GetTables(con)
        For i As Integer = 0 To dt.Rows.Count - 1
            If dt.Rows(i)("table_name").ToString() = report Then
                Return True
            End If
        Next
        Return False
    End Function
End Class