WordPress MU

1) I checked the FAQ
2) I read the Codex
3) I posted here

But I still can't get this working. Any help you can give would be much appreciated!

I have a set of sidebars that I want to display in a grid of 2 rows by four columns underneath the main content on the page. There is also a right-hand sidebar. They're each being added and controlled via Appearance > Widgets.

I can only get one sidebar (right-hand sidebar) to show up, though.

Here's my setup:

sidebar1.php - sidebar9.php

sidebar1.php contains the right-hand sidebar:

<div class="art-sidebar1">
<?php if (!art_sidebar('Right Sidebar')): ?>
<?php if ( function_exists ( dynamic_sidebar('Right Sidebar') ) ) : ?>

<?php endif; ?>
<?php endif ?>
</div>

This "Right Sidebar" is the only one I can get to display on the page. The others, defined below, don't display at all no matter what I type into the Widget for each.

sidebar2.php contains the sidebar in Row 1, Column 1 like this:

<div class="art-sidebar1">
<?php if (!art_sidebar('Under Bar R1C1')): ?>
<?php if ( function_exists ( dynamic_sidebar('Under Bar R1C1') ) ) : ?>

<?php endif; ?>
<?php endif ?>
</div>

sidebar3.php - sidebar9.php are the same as sidebar2.php, except the "R1C1" combination changes according to each sidebar's position.

Then, in my functions.php file, I have the following:

if (function_exists('register_sidebars')) {
	register_sidebars(1, array(
		'name' => 'Right Sidebar',
		'before_widget' => '<div id="%1$s" class="widget %2$s">'.'<!--- BEGIN Widget --->',
		'before_title' => '<!--- BEGIN WidgetTitle --->',
		'after_title' => '<!--- END WidgetTitle --->',
		'after_widget' => '<!--- END Widget --->'.'</div>'
	));
}

if (function_exists('register_sidebars')) {
	register_sidebars(1, array(
		'name' => 'Under Bar R1C1',
		'before_widget' => '<div id="%1$s" class="widget %2$s">'.'<!--- BEGIN Widget --->',
		'before_title' => '<!--- BEGIN WidgetTitle --->',
		'after_title' => '<!--- END WidgetTitle --->',
		'after_widget' => '<!--- END Widget --->'.'</div>'
	));
}

...and so on for each row/column "cell".

Finally, here's my setup on page.php to display the grid (this part is NOT working):

<div style="width:25%;float:left"><?php get_sidebar('Under Bar R1C1');?></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R1C2');?></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R1C3');?></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R1C4');?></div>
<div class="cleared"></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R2C1');?></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R2C2');?></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R2C3');?></div>
<div style="width:25%;float:left"><?php get_sidebar('Under Bar R2C4');?></div>
<div class="cleared"></div>

The problem appears to be with each call to "get_sidebar()". Nothing shows up with that. If I type plain HTML text where the get_sidebar calls are, the text shows up fine.