Catchable fatal error:

Hi,

I am using Mystique theme by Digital Nature, when I am navigating to next page (page 2), I am getting the following error:

Catchable fatal error: Object of class WP_Error could not be converted to string in /wp-content/themes/mystique/index.php on line 16

I have the following at line 16:
`
<?php if (have_posts()) : ?>
<?php while (have_posts()) : the_post();
$post_preview = get_mystique_option(‘post_preview’);
$category = get_the_category();
$category_link = ‘cat_ID).'”>’.$category[0]->cat_name.’‘;
if(count($category)>1) $category_link .= ‘ …’;
?>
‘

You can see the demo here: Click here

Any help would be highly appreciated.

Thanks.