MSCOMM and Access 2000

I am having a problem.  I am trying to use MSCOMM to connect and read from a serial port but my program won't run because of the following error.

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Runtime Error '91'.

Object Variable or With Block Variable not Set
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Here's my code:

If tglPortStatus.Caption = "Port Closed" Then
        Dim msComm1 As MSComm
        Dim i As Integer
     
        ' Set MSComm = New MSComm
        ' Buffer to hold input string
        Dim Instring As String
        ' Use COM1.
        With msComm1
            .CommPort = 1
            ' 9600 baud, no parity, 8 data, and 1 stop bit.
            .Settings = "9600,N,8,1"
            ' Tell the control to read entire buffer when Input
            ' is used.
            .InputLen = 0
            ' Open the port.
            .PortOpen = True
        End With
        ' Wait for data to come back to the serial port.
        Do
           DoEvents
           Buffer$ = Buffer$ & msComm1.Input
           MsgBox Buffer$
        Loop Until txtReading1.Text <> "" Or Not IsNull(txtReading1)
        ' Close the serial port.
        msComm1.PortOpen = False
        Set msComm1 = Nothing
    End If