What version did you install? 1.0? There is a serious bug on that version and it has been fixed in 1.0.1. To fix the url tag issue find
array(
'tag' => 'url',
'type' => 'unparsed_content',
'content' => '<a href="" target="_blank"></a>',
'validate' => create_function('&$tag, &$data, $disabled', '$data = strtr($data, array(\'<br />\' => \'\'));'),
),
replace with
array(
'tag' => 'url',
'type' => 'unparsed_content',
'content' => '<a href="$1" target="_blank"></a>',
'validate' => create_function('&$tag, &$data, $disabled', '$data = strtr($data, array(\'<br />\' => \'\'));'),
),
in Subs.php