file upload cakephp

when uploading an image to the server using cakephp

$this->Model->Behaviors->attach('ImageUpload', Configure::read('photo.files'));

photo uploaded successfully, and the database fields also

but shows following error instead of returning to index page.

Notice (8): Undefined index: class [CORE\cake\libs\model\behaviors\upload.php, line 104]

Notice (8): Undefined index: class [CORE\cake\libs\model\behaviors\upload.php, line 107]

Warning (2): Cannot modify header information - headers already sent by (output started at E:\umoorthy_105act10\projects\dev1base\core\cake\basics.php:111) [CORE\cake\libs\controller\controller.php, line 614]

wat to do?