Magento

After upgrade to 1.3.0, I cannot get “New Products” and “Special/Discount Products” feed only from the frontend. It produces the following error:

Warning: Illegal offset type in isset or empty in /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Catalog/Model/Resource/Eav/Mysql4/Product/Collection.php on line 997
Trace:
#0 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Catalog/Model/Resource/Eav/Mysql4/Product/Collection.php(997): mageCoreErrorHandler(2, ‘Illegal offset ...’, ‘/var/www/vhosts...’, 997, Array)
#1 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Rss/Block/Catalog/New.php(74): Mage_Catalog_Model_Resource_Eav_Mysql4_Product_Collection->addAttributeToFilter(Array, ‘’, ‘left’)
#2 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Core/Block/Abstract.php(643): Mage_Rss_Block_Catalog_New->_toHtml()
#3 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Core/Model/Layout.php(526): Mage_Core_Block_Abstract->toHtml()
#4 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Core/Controller/Varien/Action.php(339): Mage_Core_Model_Layout->getOutput()
#5 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Rss/controllers/CatalogController.php(59): Mage_Core_Controller_Varien_Action->renderLayout()
#6 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Core/Controller/Varien/Action.php(367): Mage_Rss_CatalogController->newAction()
#7 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(247): Mage_Core_Controller_Varien_Action->dispatch(’new’)
#8 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/code/core/Mage/Core/Controller/Varien/Front.php(158): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#9 /var/www/vhosts/rc-uwants.com/httpdocs/heli/app/Mage.php(457): Mage_Core_Controller_Varien_Front->dispatch()
#10 /var/www/vhosts/rc-uwants.com/httpdocs/heli/index.php(52): Mage::run()
#11 {main}

So strange. Why?

I have the same issue at time to time, noticed some error reports on online customers list, checked the error and it was exactly the same as this. Was wondering what was it.