when you have installed the latest php 5.3 and magento 1.3 and you may get an error like:
“Fatal error: Method Varien_Object::__tostring() cannot take arguments ”
you need to take the below steps:

1. open lib/Varien/Object.php (line 484)
   replace this line
   public function ___toString(array $arrAttributes = array(), $valueSeparator=’,’)

   with

   public function __invoke(array $arrAttributes = array(), $valueSeparator=’,’)
2. open index.php
   replace this line
   error_reporting(E_ALL | E_STRICT);

   with

   error_reporting(E_ALL & E_STRICT & ~E_DEPRECATED);
3. open downloader/Maged/Pear.php
   replace this line
   error_reporting(E_ALL & ~E_NOTICE);

   with

   error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED);
4. open lib/Varien/Pear.php
   replace this line
   error_reporting(E_ALL & ~E_NOTICE);

   with

   error_reporting(E_ALL & ~E_NOTICE & ~E_DEPRECATED);
   5  . Open app/code/core/Mage/Core/Controller/Request/Http.php:199 and replace

   $host = split(':', $_SERVER['HTTP_HOST']);

   with

   $host = explode(':', $_SERVER['HTTP_HOST']);

   Split has been DEPRECATED as of PHP 5.3.0.

The above steps will work for windows hosting also. Apart from that if you are on Windows server then php 5.3 will not recognize < ? and ?>. So to fix this open your php.ini file and enable

then restart your server.