That code will attempt to open the word document in-memory on the server, not on the browser. You need to display the doc file on the client's machine. To do this, set up an IFRAME or frame on your page and set the source of the IFRAME/frame to be the location of the DOC file (http location of course). If the user's browser has the plugins to read the DOC file, it'll be displayed in the browser, else they will be prompted for a download.
In either case, any changes they make to the doc file will be local to them and will not be saved back to the server.