I have limited experiance with office automation ( done some stuff with excel ), but I looks to me as though there is an object missing in your line: odoc.activate("execsummain3.doc"). Activate like a method; It's not a collection ( of objects, which the work document is ).

I'm not sure of the collection objects' name for word, but you'll need to find it. the syntax should ( i believe ) be something like:
odoc.WordDocumentCollection("execsummain3.doc").activate where WordDocumentCollection is the name of the Collection holding all the open document files.

hope that helps
- jer