I have continued to research this problem and replaced my code with this to find the Bookmark:

ActiveDocument.Bookmarks("Name1").Select
Selection.TypeText Text:=txtName.Text <--- this line is highlighted on Debug
ActiveWindow.ActivePane.Close

Now the error is:

Run-time error '424':
Object required

and the line above is highlighted on Debug.

I would be grateful for someone's help.

Regards
George