remove smarty -> assign from controller through override (PS 1.5)

[defuzed]

I modified the default prestashop 1.5 newsletter module and made the following override of to the IdentityController

 

$this->context->smarty->assign('newsletter', (int)Module::getInstanceByName('berlindisplaynewsletter')->active);

 

So the checkbox would appear to set/unset newsletter subscription via the "my personal information" account link.

Everything works fine but with ini_set("display_errors", 1); i still get the following php error on the personal info page

 

Notice: Trying to get property of non-object in /var/www/prestashop/controllers/front/IdentityController.php on line 135 Call Stack: 0.0001 646712 1.

 

line 135 of IdentityController.php is

 

$this->context->smarty->assign('newsletter', (int)Module::getInstanceByName('blocknewsletter')->active);

 

When i comment out the line, the error goes away, but I really don't want to mess with the core files, can anyone tell me how to "unset" this variable through the override file?