Is there a known issue with Blueprint's last class?

I attempted to do this Blueprint CSS tutorial, but couldn't get any elements to display in the last column. I found this solution, indicating there may be a problem with the last class, but it didn't work for me.

Has any one else experienced this issue and found a fix?

Please let me know if screenshots are needed to clarify.

<div class="container">
        <div id="dis_header" class="span-24 last">
            <h1>Heade开发者_开发百科r</h2>
        </div>
        <hr/>
        <div class="span-17 colborder" id="dis_content">
            <p>Some content here</p>
        </div>
        <!-- PROBLEM AREA -->
        <div class="span-6 last" id="dis_sidebar">
            <div class="box">
                <p>
                    This displays at the bottom instead of the right side, like it should.
                </p>
            </div>
            <div class="box">
                <p>
                    Same problem here.
                </p>
            </div>
        </div>
        <hr/>
    </div>

This is not an issue with Blueprint CSS. When I access the web page using 127.0.0.1 as my local, I see the misplaced divs. When I access using localhost, everything is placed as expected.

I have not looked into this more deeply, since the problem is "solved" from my perspective, but feel free to post a comment if you've ever seen this before.