<div class="row-fluid">
   <div class="span6">...</div>
   <div class="span6">...</div>
</div>

Adding columns to an article is simple when the template is bootstrapped.  No special plugin or addon is required.  I use the Sparky Framework for Joomla and WordPress so this is quite simple to implement with this code sample.  The above sample will give you a two column layout.

<div class="row-fluid">
   <div class="span6">...</div>
   <div class="span3">...</div>
   <div class="span3">...</div>
</div>

Play with the code a bit to achieve a 3 or 4 column layout. I also have used these codes to display modules inside the columns using the plugin Modules Anywhere by NoNumber. 

If you've gotten this error "JFolder::create: Could not create directory Warning! - Failed to move file" this most likely is due to the misconfiguration of your configuration.php file.  This will happen with Joomla, Wordpress, Drupal and any CMS that has a configuration.php file.