I just started getting this error in my exceptions log file. I'm running 1.7.0.2 and nothing has been touched on the site in a long time and this is popping up repeatedly.
exception 'Mage_Core_Exception' with message 'Invalid block type: ' in /chroot/home/thoughtt/thoughttechnology.com/html/app/Mage.php:598
Stack trace:
#0 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/Layout.php(495): Mage::throwException('Invalid block t...')
#1 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/Layout.php(437): Mage_Core_Model_Layout->_getBlockInstance('', Array)
#2 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/Layout.php(472): Mage_Core_Model_Layout->createBlock('', 'product.info.bu...')
#3 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/Layout.php(239): Mage_Core_Model_Layout->addBlock('', 'product.info.bu...')
#4 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/Layout.php(205): Mage_Core_Model_Layout->_generateBlock(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#5 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/Layout.php(210): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#6 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Controller/Varien/Action.php(344): Mage_Core_Model_Layout->generateBlocks()
#7 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Catalog/Helper/Product/View.php(73): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#8 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Catalog/Helper/Product/View.php(144): Mage_Catalog_Helper_Product_View->initProductLayout(Object(Mage_Catalog_Model_Product), Object(Mage_Catalog_ProductController))
#9 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Catalog/controllers/ProductController.php(132): Mage_Catalog_Helper_Product_View->prepareAndRender(206, Object(Mage_Catalog_ProductController), Object(Varien_Object))
#10 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Controller/Varien/Action.php(419): Mage_Catalog_ProductController->viewAction()
#11 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('view')
#12 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#13 /chroot/home/thoughtt/thoughttechnology.com/html/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#14 /chroot/home/thoughtt/thoughttechnology.com/html/app/Mage.php(687): Mage_Core_Model_App->run(Array)
#15 /chroot/home/thoughtt/thoughttechnology.com/html/index.php(108): Mage::run('', 'store')
#16 {main}
