Have you enabled comments for the post? This must be done when editing a single post. If the comment options are not visible when editing the post, select the screen options link from the top right of the page and tick comments.
blocblue
Practically a Posting Shark
837 posts since Jan 2008
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Have you unticked the box in the Settings->discussion to not allow comments (Allow people to post comments on new articles )?
simplypixie
Practically a Master Poster
642 posts since Oct 2010
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