cant add something new get this error masage

I need help what can be

Platform information

Host name: NSA325
Operating system: Linux 2.6.31.8
Apache: Apache/2.2.9 (Unix) mod_ssl/2.2.9 OpenSSL/0.9.8o PHP/5.2.8 mod_wsgi/2.4 Python/2.6.2
PHP: 5.2.8
MySQL: 5.1.30
Server load: 0.38 0.19 0.21
Graphics toolkit: imagemagick

Gallery stats

Version: 3.0.4 (Ricochet)
Albums: 4
Photos: 317

Database_Exception [ Database Error ]: #1062: Duplicate entry '336' for key 'PRIMARY' [ INSERT INTO `items` (`created`, `rand_key`, `thumb_dirty`, `resize_dirty`, `sort_column`, `sort_order`, `owner_id`, `type`, `parent_id`, `name`, `title`, `description`, `slug`, `updated`, `weight`, `left_ptr`, `right_ptr`, `level`) VALUES (1386758039, 0.186856, 1, 1, 'created', 'ASC', '2', 'album', '1', 'Kroatien', 'Kroatien', '', 'Kroatien', 1386758039, 334, 650, 651, 2) ]

SYSPATH/libraries/Database_Mysql_Result.php[ 27 ]
22 } 23 elseif (is_bool($result)) 24 { 25 if ($result == FALSE) 26 { 27 throw new Database_Exception('#:errno: :error [ :query ]', 28 array(':error' => mysql_error($link), 29 ':query' => $sql, 30 ':errno' => mysql_errno($link))); 31 32 }

SYSPATH/libraries/Database_Mysql.php[ 124 ] » Database_Mysql_Result_Core->__construct( arguments )

SYSPATH/libraries/Database.php[ 272 ] » Database_Mysql_Core->query_execute( arguments )

MODPATH/gallery/libraries/MY_Database.php[ 45 ] » Database_Core->query( arguments )

SYSPATH/libraries/Database_Builder.php[ 973 ] » Database->query( arguments )

SYSPATH/libraries/ORM.php[ 823 ] » Database_Builder_Core->execute( arguments )

MODPATH/gallery/libraries/MY_ORM.php[ 34 ] » ORM_Core->save()

MODPATH/gallery/libraries/ORM_MPTT.php[ 76 ] » ORM->save()

MODPATH/gallery/models/item.php[ 370 ] » ORM_MPTT_Core->save()

MODPATH/gallery/controllers/albums.php[ 127 ] » Item_Model_Core->save()

{PHP internal call} » Albums_Controller->create( arguments )

SYSPATH/core/Kohana.php[ 331 ] » ReflectionMethod->invokeArgs( arguments )

{PHP internal call} » Kohana_Core::instance( arguments )

SYSPATH/core/Event.php[ 208 ] » call_user_func_array( arguments )

APPPATH/Bootstrap.php[ 67 ] » Event_Core::run( arguments )

DOCROOT/index.php[ 113 ] » require( arguments )

Environment