This seems to be a WordPress issue rather than a Thematic issue, but I haven't been able to find an answer, and in searching the WordPress forums it seemed that most questions were unanswered, whereas here people are helping each other, so I will ask you guys.
I added "more" comment tags to my posts so my homepage would show excerpts. But this resulted in WordPress failing to close tags if the "more" came in the middle of a tag. This invalidated the page and caused the asides to move into the content column.
I've solved it by removing all the "more" tags, but I really wanted excerpts on the home page. Is there a way around this?