Checked ListView Count - NullReferenceException

Win XP, VS 2008, .NET 2.0

When I use Count property to count checked items in ListView (set to detail view with check boxes), sometimes i get NullReferenceException on count part. Sometimes I get it but sometimes I don't get it... It's very randomly and I can not reproduce it always?!? It just happens sometimes :confused:
Can somebody tell me why or point me a lil bit?

VB.Net Code:

CODE:
Private Sub LstVew1_ItemChecked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ItemCheckedEventArgs) _
Handles LstVew1.ItemChecked
   If LstVew1.CheckedItems.Count > 1 Then
     lbl1.Text = "Selected items: " & LstVew1.CheckedItems.Count
   Else
     lbl1.Text = "U have 1 or 0 selected item(s)"
   End If
End Sub
 
CODE EXCEPTION:
System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Windows.Forms.ListView.CheckedIndexCollection.get_Count()
   at System.Windows.Forms.ListView.CheckedListViewItemCollection.get_Count()
   at ...

Thanks in advance

Try and figure out what is null. Is it the listview or is it the checked collection?

Do you ever call .Dispose on the listview?

The problem is that I really don't know for sure on which part is error exactly while this never happened in debuger (in vs environment). This happens on rare occasions (like 1 per week) and in exe file on some machine... Never on my machine :(

- I don't call dispose for list view. Do u think that not disposing it cause souch problems? I can not dispose it while I use it when is form opened. ListView is filled with data and when using it, some data gets checked by user some gets unchecked, so I need it and i cant dispose it.

Yesterday evening I heard some guys talking about that they get exactly the same error on listview.checked.count part and they suspect .net 2 framework bug. Hmmm. If that is the case can i count it in another way... more safer way?

New updates on this bug.

I isolated this bug to users that have installed on their computers maximum original .NET framework 2 with no service pack and no .net 3 and no .net 3.5. Strange that affects only users with NET 1/1.1 and NET 2. Other users seems to be fine...

If that is the case, I am now interested in finding another way to count checked items in listview? Is there?