Problem displaying video in Rhythm theme

I'm using the Rhythm theme and want to display video clips in the primary content area of the item page (/item/show.php). The video clips display in the secondary content area (sidebar), but the primary only displays an associated still image.

I tried pasting in code from the secondary div to the primary div, but that didn't work (couldn't load pages).

Any suggestions? Here's an example:

When you say you couldn't load the page, did you get a white screen, an error, partial view of metadata or styling?

Did you cut everything related to the files from the secondary div, falling within the <dd> tags, into the primary div?

Where did you paste? Try it after other divs have closed, such as after the metadata just above the
<?php echo plugin_append_to_items_show(); ?>

That worked, but the video shows up too low on the page (because I have a still image associated with the item, first) and runs into the footer. So I pasted the code right after the title and that looks much better.

However, now all items (other than those with a video file) appear with the statement: "No files are associated with this item" right above the displayed image of the item. So I struck the following:

<!-- <?php if (!$hasShownFile): ?>
No files are associated with this item.
<?php endif; ?> -->

And now it seems to work well. So I gather there is a distinction between an item "image" and an item "file." Is this something I can manage in the Item editing interface?

Thanks for your help!