Adding a CommandBarButton to the CommandBar

[iamsuperman]

I am trying to create a COM Add-in for the MS Word and I wrote the following function of which I used to add a CommandBarButton to the "Web" CommandBar in the MS Word. When this function was called during the startup of MS Word in the OnStartupComplete(), the following error message displayed:

http://hk.geocities.com/saratara_me/errmsg.JPG

Could anybody please tell me what the problems could possibly be?

Many thanks to you all!

Public Function AddToCommandBar() As CommandBarButton
 
Dim cbb As CommandBarButton
Dim Cnt As Integer
 
Cnt = Application.CommandBars("Web").Controls.Count
 
Set cbb = Application.CommandBars("Web").Controls.Add(Type:=msoControlButton, Id:=2950, Before:=Cnt + 1)
 
Set AddToCommandBar = cbb
 
End Function