Are you trying to reference the built-in Help popup menu in your example? If so, your code won't work because this control is not assigned a Tag value.
I don't think any built-in Office commandbar controls are assigned Tag values, in fact
You need to either use the ID parameter, or refer to it by it's key name in the collection. I've always done the former, by preference.
Code:
Set helpPopup = Application.CommandBars("Worksheet Menu Bar").FindControl(Id:=30010)
the above should work fine to locate the built-in Help popup.