This is a script error not a coding problem (ie it's on the webpage).
You can stop it simply by setting:
Webbrowser1.ScriptErrorsSuppressed = True
This will also stop some authentication boxes etc though so you are better of using:
AddHandler Webbrowser1.DocumentCompleted, AddressOf webbrowser1_DocumentCompleted
Private Sub webbrowser1_DocumentCompleted(ByVal sender As Object, ByVal e As WebBrowserDocumentCompletedEventArgs)
AddHandler CType(sender, WebBrowser).Document.Window.Error, AddressOf Window_Error
End Sub
Private Sub Window_Error(ByVal sender As Object, _
ByVal e As HtmlElementErrorEventArgs)
' Ignore the error and suppress the error dialog box.
e.Handled = True
End Sub