Problem with admin cotroller

The admin structure where items can be inserted like products. There are functions like Insert, copy, update, delete, etc. They all have redirects like that :
$response->redirect(&this->url->link('catalog/product', token(....) .$url, ));

when I insert a new product, Edit or copy them, it must be redirected back to the initial page you where,

But it doesn't work, and I counter to a white page.
i.e:
http://domin.com/admin/index.php?route= ... opy&token=......

must be redirected to

http://domin.com/admin/index.php?route= ... uct&token=......

I recently have changed this php code, but after receiving this error I changed back it to it's original code but the problem is still remained.
How can I solve the problem
Best Regards