To anyone using autoTweet that is having an issue with products description not posting to facebook, it is more than likey caused by another mod adding to your description field (such as: FCKeditor Plugin).

Adding
PHP Code:
$prod_description = strip_tags($prod_description); 
Below (line 105) where you see:
PHP Code:
    //$prod_description = implode(" ", $_POST['products_description']); 
And that should fix it.