Undefined index: URL [APP/View/Clients/index.ctp, line 90]

Undefined index: URL [APP/View/Clients/index.ctp, line 90]

I have been asked to work on aplication someone else has created with
cakePHP. I am new to cakePHP.The application shows the following errors
Notice(8):
if(isset($client[0]) && $client[0]['contacts']['type_of']==3 &&
$var=='clients_with_contacts' && $this->Paginator->current()==1){
echo '<td
style="background:lightblue">'.$client[0]['Client'][$field].'</td>';
include - APP/View/Clients/index.ctp, line 90
View::_evaluate() - CORE/Cake/View/View.php, line 947
View::_render() - CORE/Cake/View/View.php, line 909
View::render() - CORE/Cake/View/View.php, line 471
Controller::render() - CORE/Cake/Controller/Controller.php, line 948
Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 194
Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 162
[main] - APP/webroot/index.php, line 112
There is a ton of code.If you can think of anything let me know.