Undefined index on Admin panel

can anyone help me

Notice: Undefined index: weight_class_id in /home/purecigg/public_html/admin/model/catalog/product.php on line 130Notice: Undefined index: length_class_id in /home/purecigg/public_html/admin/model/catalog/product.php on line 130Warning: Cannot modify header information - headers already sent by (output started at /home/purecigg/public_html/admin/controller/startup/error.php:34) in /home/purecigg/public_html/system/storage/modification/system/library/response.php on line 12

No because: read first the forum rules and post again.
Thanks!