I think this is something I'll need to account for in the template. What it appears from looking at the box is that your links are using a slightly smaller font than non-links. We're using a float to align the post totals to the right, but since the link text is a bit smaller it's not completely clearing to the next line.
You can try this and see if it fixes it. Open up your island_top_posters.tpl file. Line 15 has this:
Try changing that, to this:
<div style="clear: both"></div>
{/section}
Once that change is made, go into the control panel and clear the cache.
