CSS blocks creating empty "cells"

I thought I fixed this, but it's started going crazy again.

Basically, I coded my friend's portfolio using ModX and CSS. But when it loads the blocks, sometimes there is a blank one. It's much easier to just see as opposed to my trying to explain: http://www.erinkong.com/index.php?id=47.

Here is the code that loads each individual block:
<div class="galleryblock"><a href="[~[+id+]~]"><img src="[+image+]" width="175" height="130" border="0" /><br />[+pagetitle+]</a></div>

And here is the css for the div class:

.galleryblock {
	display: inline;
	width: 200px;
	float: left;
	position: relative;
	text-align: center;
	padding-top: 20px;
	vertical-align: top;
}

I thought I had fixed this. Gahhh!

Thank you!

-Laura