Adding Column Classes Functions Not Working

Hi there,
I wanted to split the results into columns. I have see your code here: http://www.billerickson.net/code/add-column-classes-to-display-posts-shortcodes/ and I am using Genesis, so I have the correct style sheet. However, your code doesn’t seem to work, as each listing simply adds “first” to every div class (the div class becomes: <div class=”listing-item one-third first”>), so that each listing is cleared (clear:both). For some reason your if statement:
if( 0 == $listing->current_post || 0 == $listing->current_post % 3 )
$classes[] = ‘first’;

Always returns true and adds first to ever div class in the list.

Any ideas what’s going here?

http://ww.wp.xz.cn/extend/plugins/display-posts-shortcode/