error คะ รบกวนดูให้หน่อยนะคะ มันขึ้น error แบบนี้อ่ะคะ เป็น web app ใช้ visual studio 2008 กับ my sql

Dim objConn As System.Data.OleDb.OleDbConnection 
Dim objCmd As System.Data.OleDb.OleDbCommand 
Dim strConnString As String
strConnString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="&Server.MapPath("database/mydatabase.mdb")&";Jet OLEDB:Database Password=;"
objConn = New System.Data.OleDb.OleDbConnection(strConnString) 
objConn.Open() 
Dim strSQL As String
strSQL = "SELECT * FROM customer"
Dim dtReader As System.Data.OleDb.OleDbDataReader 
objCmd = New System.Data.OleDb.OleDbCommand(strSQL, objConn) 
dtReader = objCmd.ExecuteReader()  
 
'*** DataReader ***' 
dtReader.Close() 
dtReader = Nothing
objConn.Close() 
objConn = Nothing

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim ConnString = "Server=192.168.10.88;database=pt;UID=root;"
        Dim Conn = New MySqlConnection(ConnString)
        Conn.Open()
        Dim dtAdapter As New MySqlDataAdapter
        Dim ds As New Data.DataSet

        Dim t1 = TextBox1.Text & " 00:00:00 "
        Dim t2 = TextBox2.Text & " 00:00:00 "
        Dim SQL = "select  ecode,em_name,em_name2,indate,shift,time0,time1,time2, time3, time4, time5, time6, time7, tin, tbout, tbin, tout from shifttime,emper  where(substring(em_code, 1, 7) = ecode) and indate between 't1' and  't2' and ebranch = '" & TextBox3.Text & "' order by indate,ecode "
        Dim Cmd = New MySqlCommand(SQL, Conn)
        Dim dtreader = Cmd.ExecuteReader()
        dtAdapter.SelectCommand = Cmd 'Adapter เป็นตัวเชื่อมระหว่างฐานข้อมูลกับตัวระบบ
        dtAdapter.Fill(ds) 'เป็นการรันsql
        GridView1.DataSource = ds
        GridView1.DataBind()
        dtreader.Close()
        dtreader = Nothing
    End Sub
End Class

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim ConnString = "Server=192.168.10.88;database=pt;UID=root;"
        Dim Conn = New MySqlConnection(ConnString)

        If Conn.State = ConnectionState.Open Then
             Conn.Close()
        End If

        Conn.Open()
        Dim dtAdapter As New MySqlDataAdapter
        Dim ds As New Data.DataSet

        Dim t1 = TextBox1.Text & " 00:00:00 "
        Dim t2 = TextBox2.Text & " 00:00:00 "
        Dim SQL = "select  ecode,em_name,em_name2,indate,shift,time0,time1,time2, time3, time4, time5, time6, time7, tin, tbout, tbin, tout from shifttime,emper  where(substring(em_code, 1, 7) = ecode) and indate between 't1' and  't2' and ebranch = '" & TextBox3.Text & "' order by indate,ecode "
        Dim Cmd = New MySqlCommand(SQL, Conn)
        Dim dtreader = Cmd.ExecuteReader()
        dtAdapter.SelectCommand = Cmd 'Adapter เป็นตัวเชื่อมระหว่างฐานข้อมูลกับตัวระบบ
        dtAdapter.Fill(ds) 'เป็นการรันsql
        GridView1.DataSource = ds
        GridView1.DataBind()
        dtreader.Close()
        dtreader = Nothing
    End Sub
End Class

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim ConnString = "Server=192.168.10.88;database=pt;UID=root;"
        Dim Conn = New MySqlConnection(ConnString)

        If Conn.State = ConnectionState.Open Then
             Conn.Close()
        End If

        Conn.Open()
        Dim ds As New Data.DataSet

        Dim t1 = TextBox1.Text & " 00:00:00 "
        Dim t2 = TextBox2.Text & " 00:00:00 "
        Dim SQL = "select  ecode,em_name,em_name2,indate,shift,time0,time1,time2, time3, time4, time5, time6, time7, tin, tbout, tbin, tout from shifttime,emper  where(substring(em_code, 1, 7) = ecode) and indate between 't1' and  't2' and ebranch = '" & TextBox3.Text & "' order by indate,ecode "
        Dim Cmd = New MySqlCommand(SQL, Conn)
        Dim dtreader = Cmd.ExecuteReader()

        GridView1.DataSource = dtreader
        GridView1.DataBind()
        dtreader.Close()
        dtreader = Nothing
    End Sub
End Class

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim ConnString = "Server=192.168.10.88;database=pt;UID=root;"
        Dim Conn = New MySqlConnection(ConnString)

        Dim dtAdapter As New MySqlDataAdapter
        Dim ds As New Data.DataSet

        Dim t1 = TextBox1.Text & " 00:00:00 "
        Dim t2 = TextBox2.Text & " 00:00:00 "
        Dim SQL = "select  ecode,em_name,em_name2,indate,shift,time0,time1,time2, time3, time4, time5, time6, time7, tin, tbout, tbin, tout from shifttime,emper  where(substring(em_code, 1, 7) = ecode) and indate between 't1' and  't2' and ebranch = '" & TextBox3.Text & "' order by indate,ecode "
        Dim Cmd = New MySqlCommand(SQL, Conn)
        dtAdapter.SelectCommand = Cmd 'Adapter เป็นตัวเชื่อมระหว่างฐานข้อมูลกับตัวระบบ
        dtAdapter.Fill(ds) 'เป็นการรันsql
        GridView1.DataSource = ds
        GridView1.DataBind()
    End Sub
End Class