Searching Twice gives Object reference null

'Button1

Dim ex1 As New Threading.Thread(AddressOf ex1_sub)

Dim ex2 As New Threading.Thread(AddressOf ex2_sub)

ex1.Start()
ex2.Start()
'End Sub

Sub ex1_sub()

Dim result_ex1 As IWebResult

Dim client_ex1 As New GwebSearchClient("http://www.google.com")

Dim results_ex1 As IList(Of IWebResult) = client_ex1.Search("love", 2)

For Each result_ex1 In results_ex1
MsgBox(result_ex1.Title)
Next

End Sub


Sub ex2_sub()
Dim result_ex2 As IWebResult

Dim client_ex2 As New GwebSearchClient("http://www.google.com")

Dim results_ex2 As IList(Of IWebResult) = client_ex2.Search("hate", 2)

For Each result_ex2 In results_ex2
MsgBox(result_ex2.Title)
Next

End Sub

It points either to results_ex2 or results_ex1 and tells me Object reference not set to an instance of an object.

How could I fix that ?