NullReferenceException was unhandle when loop an object

[huskar]

Hi Everyone!
I got two form.
form 1 i ask the user a number of guest
form 2 i ask each guest their name, their age
i decide to make a loop base on the number of guest but then i got this error. NullReferenceEx ception was unhandled
how to solve this...i underline under my code

Private Sub btnBook_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBook.Click

        iTest = CInt(txtChildren.Text)
        Do Until (iCounter = iTest) And (bIsNextClicked = True)
            PassengersDetails(iCounter).[U]ShowDialog()[/U]
        Loop

    End Sub

[PsychoCoder]

I would start with putting a break point on line 4 to see what value ICounter holds.