vba error 424

Hello,
can you please help,
I'm getting error 424, Object required on line
    Set rngLastCell = Sheet1.Cells(Sheet1.Rows.Count, strColumn)

Sub Insert()

    Dim cnn As adodb.Connection
    Dim strConnectionString As String
    Dim sh As Worksheet
    Dim strInsert As String
    Dim lngRow As Long

    Set sh = Sheets("Settlements")
    Set cnn = New adodb.Connection
     strConnectionString = "Provider=SQLOLEDB.1;User ID=sa; password=cccccccc!;Initial Catalog=xxxxx;Data Source=Wassim-XPS;"

    'Start
    cnn.Open strConnectionString

    For lngRow = 2 To LastUsedCell("A")
        strInsert = "INSERT INTO DriverSettlementMessages (DriverSettlementNo, DriverNumber, CompanyID, DateInserted) " & _
                    " VALUES (" & _
                    sh.Cells(lngRow, 1) & ", " & _
                    sh.Cells(lngRow, 2) & ", " & _
                    sh.Cells(lngRow, 3) & ", " & _
                    "'" & sh.Cells(lngRow, 4) & "')"

    cnn.BeginTrans
    cnn.CommitTrans

        On Error Resume Next
        cnn.Execute strInsert
    Next lngRow

    cnn.BeginTrans
    cnn.CommitTrans

        MsgBox "Done"
End Sub
                                           
Public Function LastUsedCell(strColumn As String) As String
    Dim rngLastCell As Range
    Set rngLastCell = Sheet1.Cells(Sheet1.Rows.Count, strColumn)

    If IsEmpty(rngLastCell.Value2) Then
        LastUsedCell = rngLastCell.End(xlUp).Row
    Else
        LastUsedCell = rngLastCell.Row
    End If
End Function