If a post is awaiting approval which has an empty subject, the link that would normally appear allowing you to visit the post in the moderation queue page is empty (no text) and so cannot be clicked on.

The workaround is to click on the topic link and manually search through the topic until the post is found, but for large topics this becomes impractical.

Some more details: On the main moderator control panel page, where the latest 5 posts to be approved are displayed, the empty subject is replaced by the text "No subject specified" which can be properly clicked on. But on the "posts waiting approval" section of the moderation queue tab, this replacement does not occur and the subject remains completely blank.