I could be dead wrong here, but since .doc is associated with certain programs, you may not be able to display it within a browser window. The browser will try to start the proper application to view a .doc file.
Instead of just retriving the document for display, you may be able to assign the contents of that file to a variable, and then simply print out the variable.
This is nothing more than a guess, since I have never tried to do what you are attempting. Best of luck!
