No Sidebars Defined

Hello,

I’m getting the “No Sidebars Defined, The theme you are currently using isn’t widget-aware…” message when I hit my Appearance > Widget tab – and my side bar stuff doesn’t show up (a photo gallery) on the site. All of this was working fine, I believe, until I installed a new widget (Thumbnail for Excerpt widget). I’ve since deactivated, and then removed the new widget, upgraded to the last version of WordPress, deactivated other widgets – all to no avail. I’ve also read extensively and tried out updating the function.php and sidebar.php files – still doesn’t work – no side bar widgets and same message as above.

Currently in my functions.php I have this code:

if ( function_exists('register_sidebar') )
    register_sidebar(array(
        'before_widget' => '<li id="%1$s" class="widget %2$s">',
        'after_widget' => '</li>',
        'before_title' => '<h2 class="widgettitle">',
        'after_title' => '</h2>',
    ));

and in the sidebar.php code I have:

if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar() ) : ?>

I’ve read many sites and tried different variation of the above code – but still nothing. I can’t link to the site because it is behind a “firewall/secure set up”

Thanks to anyone that can give me clue here?