Boa Noite

como resolvo este erro desta formula, o erro esta em negrito

If CDate(Cells(a, "A")) = Dia Then

Function retornaDiaMesEAno(ByVal Dia As Date, ByVal Mes As String, ByVal Ano As Integer)
    
    somaVendasDia = "0"
    somaVendasMes = "0"
    somaVendasAno = "0"
    somaComprasDia = "0"
    somaComprasMes = "0"
    somaComprasAno = "0"
    somaPrazoDia = "0"
    somaPrazoMes = "0"
    somaPrazoAno = "0"
    
    Application.ScreenUpdating = False
    
    With ThisWorkbook.Sheets("Compras")
        .Activate
        For A = 4 To .UsedRange.Rows.Count
            If Cells(A, "A") <> "" Then
                Cells(A, "A").Select
                If CDate(Cells(A, "A")) = Dia Then
                    somaComprasDia = somaComprasDia + CDbl(Format(Cells(A, "E"), "currency"))
                End If
                If Mid(Cells(A, "A"), 4, 2) = Mes Then
                    somaComprasMes = somaComprasMes + CDbl(Format(Cells(A, "E"), "currency"))
                    If Mid(Cells(A, "A"), 7, 4) = Ano Then
                        somaComprasAno = somaComprasAno + CDbl(Format(Cells(A, "E"), "currency"))
                    End If
                End If
            End If
        Next
    End With
    
    With ThisWorkbook.Sheets("Vendas")
        .Activate
        For A = 4 To .UsedRange.Rows.Count
            Cells(A, "A").Select
            If Cells(A, "A") <> "" Then
                If CDate(Cells(A, "A")) = Dia Then
                    somaVendasDia = somaVendasDia + CDbl(Format(Cells(A, "E"), "currency"))
                End If
                If Mid(Cells(A, "A"), 4, 2) = Mes Then
                    somaVendasMes = somaVendasMes + CDbl(Format(Cells(A, "E"), "currency"))
                    If Mid(Cells(A, "A"), 7, 4) = Ano Then
                        somaVendasAno = somaVendasAno + CDbl(Format(Cells(A, "E"), "currency"))
                    End If
                End If
            End If
        Next
    End With
    
    With ThisWorkbook.Sheets("Prazo")
        .Activate
        For A = 4 To .UsedRange.Rows.Count
            Cells(A, "A").Select
            If Cells(A, "A") <> "" Then
                If CDate(Cells(A, "A")) = Dia Then
                    somaPrazoDia = somaPrazoDia + CDbl(Format(Cells(A, "E"), "currency"))
                End If
                If Mid(Cells(A, "A"), 4, 2) = Mes Then
                    somaPrazoMes = somaPrazoMes + CDbl(Format(Cells(A, "E"), "currency"))
                    If Mid(Cells(A, "A"), 7, 4) = Ano Then
                        somaPrazoAno = somaPrazoAno + CDbl(Format(Cells(A, "E"), "currency"))
                    End If
                End If
            End If
        Next
    End With
    ThisWorkbook.Sheets("Menu").Activate
    Application.ScreenUpdating = True
    
End Function