error for export data to word

1.Do you add reference Microsoft Word 10.0 Object Library?
After adding reference you can create instance like:

Word.ApplicationClass oWordApp = new Word.ApplicationClass();

See..
Microsoft Word Documents from ASP.NET[^]

2.You can use Microsoft.Office.Interop.Word Namespace and do something like:

Application application = new Application();
Document document = application.Documents.Open("C:\\word.doc");