[racket] web applications example problem

i started on the web applications blog example a couple weeks ago in
Dr Racket. Did maybe 5-10 minutes of simple work to play around
then went to work on other stuff unrelated to racket for a while. I
decided to start over but just trying to run:


#lang web-server/insta

(define-struct post (title body))

(struct	post (title body)
  #:extra-constructor-name make-post)
title : string?
body : string?


now gets me the error:

module: duplicate definition for identifier in: struct:post

Apparently something I did before is still hanging around. I'm not
sure where to look in order to remove.
Any help would be appreciated. I'm using DrRacket 5 on a Mac.