Vb.net Error then use form4.show - vb.net

I have a little problem with my program. I just maked a little program. I have a problem with code "Form4.Show()".
I put this code on button and then press button I receive error:
An error occurred creating the form. See Exception.IneerException for details. The error is: Object reference not set to an instance of an object.
I don't know what code I put wrong ... this button have only form4.show.
PS: this error is from try catch.
This is button code.
Try
Form4.Show
Catch ex as Exception
MessageBox.Show(ex.Message)
End Try
edit: all form4 code
Public Class Form4
Dim txt As String = Textbox1.Text
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
txt = "450IP-Gift"
Form5.Show()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
txt = "450IP"
Form5.Show()
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
txt = "1150IP-Gift"
Form5.Show()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
txt = "1150IP"
Form5.Show()
End Sub
Private Sub Button6_Click(sender As Object, e As EventArgs) Handles Button6.Click
txt = "3150IP-Gift"
Form5.Show()
End Sub
Private Sub Button5_Click(sender As Object, e As EventArgs) Handles Button5.Click
txt = "3150IP"
Form5.Show()
End Sub
Private Sub Button12_Click(sender As Object, e As EventArgs) Handles Button12.Click
txt = "4800IP-Gift"
Form5.Show()
End Sub
Private Sub Button11_Click(sender As Object, e As EventArgs) Handles Button11.Click
txt = "4800IP"
Form5.Show()
End Sub
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
txt = "6300IP-Gift"
Form5.Show()
End Sub
Private Sub Button9_Click(sender As Object, e As EventArgs) Handles Button9.Click
txt = "6300IP"
Form5.Show()
End Sub
Private Sub Button8_Click(sender As Object, e As EventArgs) Handles Button8.Click
txt = "9600IP-Gift"
Form5.Show()
End Sub
Private Sub Button7_Click(sender As Object, e As EventArgs) Handles Button7.Click
txt = "9600IP"
Form5.Show()
End Sub
Private Sub Button13_Click(sender As Object, e As EventArgs) Handles Button13.Click
Me.Close()
End Sub
End Class

You need to initialize form4
Try
Dim form4 = New Form4()
form4.Show()
Catch ex as Exception
MessageBox.Show(ex.Message)
End Try

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Umm did you type this yourself or generate it from a UI? Shouldn't it be button_OnClick not button_click?