Magento Error: Method Varien_Object::__tostring() cannot take arguments
Another straight to the point solution

Method Varien_Object::__tostring() cannot take arguments
and you have PHP 5.3 or newer then you have 2 options:1) downgrade to PHP 2.9
2) fix the bugs
If downgrading is not possible try doing these changes in Magento files:
File:
/lib/Varien/Object.php
Original text:public function ___toString(array $arrAttributes = array(), $valueSeparator=’,')
Change to:public function __invoke(array $arrAttributes = array(), $valueSeparator=’,')
File:
/app/code/core/Mage/Core/Controller/Request/Http.php
Original text:$host = split(‘:’, $_SERVER['HTTP_HOST']);
Change to:
$host = explode(‘:’, $_SERVER['HTTP_HOST']);
Comments