Need help with program containing Financial.DDB method

[CJ Densmore]

Hello, any help would be greatly appreciated:

I am trying to code a program that takes 2 testbox and a list box contain 3 to 20 years and use the financial.ddb method to output a string cont of "year depriciation" + the financial.ddb calculation. I debug teh program and I keep getting an Argument 'Factor' is not a valid on the financial.ddb calculation line. Can someone assist me and tell me if I coded the program correctly? Here is my code:

Code

Public Class Form1

Private Sub exitButton2_Cli ck(ByVal sender As Object, ByVal e As System.EventArg s) Handles exitButton2.Cli ck
Me.Close()

End Sub


Private Sub Form1_Load(ByVa l sender As Object, ByVal e As System.EventArg s) Handles Me.Load
Dim code As Integer = 3
Do While code <= 20
lifeListBox.Ite ms.Add(code.ToS tring)
code = code + 1
Loop
End Sub

Private Sub calculateButton 1_Click(ByVal sender As Object, ByVal e As System.EventArg s) Handles calculateButton 1.Click
Dim cost As Double
Dim life As Boolean
Dim salvage As Double
Dim period As Double
Dim number As Integer = 1
Dim startNdx As Integer
Dim highNdx As Integer
Dim fddb As Integer

Double.TryParse (costTextBox1.T ext, cost)
Double.TryParse (lifeListBox.Te xt, life)
Double.TryParse (salvagTextBox. Text, salvage)
period = 2
If cost AndAlso life AndAlso salvage Then
equateTextBox1. Text = " Year Depriciation"
For curNdx = startNdx To highNdx
fddb = Financial.DDB(c ost, salvage, life, period)

equateTextBox1. Text = lifeListBox.Tex t + fddb

Next



Else
MessageBox.Show ("ERROR")

End If



End Sub
End Class

/code

I have attached a screen shot of the input gui...

Thanks guys, you are a life saver!