Solved it!
This is what I used:
<div style="position: absolute;right: 250px;z-index: 4;">
<?php if ( is_page('Home') ) : ?>
<?php if ( !dynamic_sidebar('Sidebar-Demo') ) : ?><?php endif ; ?>
<?php else : ?>
<!-- This content shows up if there are no widgets defined in the backend. -->
<div class="alert alert-message">
<p><?php _e("Please activate some Widgets","limitless"); ?>.</p>
</div>
<?php endif; ?>
</div>
