I suspect the problem is in my open code

Sub Item_Open()
'Get form's Inspector and Page
Set oInspector = Item.GetInspector
Set oPageGeneral = oInspector.ModifiedFormPages("General")
End Sub

Tried this

Sub Item_Close()
Set oPageGeneral = Nothing
'oInspector.Close 1 - causes an error
Set oInspector = Nothing
End Sub

- it didn't help. Might be something I missed?