HELP! I keep receiving an error There has been an error processing your request

Hi,
I have been trying to create a staging site for a while now. I created a copy of my site and moved it to a sub domain and ETC following this quide http://www.crucialwebhost.com/kb/set...-staging-area/. I always seem to get this error though at the end that my live site doesnt have. I dont know how to fix it and whats happening.

Thanks any help is apreciated.






There has been an error processing your request
Cannot send headers; headers already sent in /home/scentual/staging/app/Mage.php, line 766

Trace:
#0 /home/scentual/staging/lib/Zend/Controller/Response/Abstract.php(115): Zend_Controller_Response_Abstract->canSendHeaders(true)
#1 /home/scentual/staging/app/code/core/Mage/Core/Model/App.php(1246): Zend_Controller_Response_Abstract->setHeader('Content-Type', 'text/html; char...')
#2 /home/scentual/staging/var/cache/ew/files/Mage/Core/Controller/Varien/Front/8b52e7f857fef0572cf21f0a3352151f.php(99): Mage_Core_Model_App->getResponse()
#3 /home/scentual/staging/var/cache/ew/files/Mage/Core/Controller/Varien/Router/Standard/088bf81233af8a733a03eb4d9a3bcae0.php(221): Mage_Core_Controller_Varien_FrontOverriddenClass->getResponse()
#4 /home/scentual/staging/var/cache/ew/files/Mage/Core/Controller/Varien/Front/8b52e7f857fef0572cf21f0a3352151f.php(191): Mage_Core_Controller_Varien_Router_StandardOverrid denClass->match(Object(Mage_Core_Controller_Request_Http) )
#5 /home/scentual/staging/app/code/local/Extendware/EWPageCache/Controller/Override/Mage/Core/Varien/Front.php(32): Mage_Core_Controller_Varien_FrontOverriddenClass->dispatch()
#6 /home/scentual/staging/app/code/core/Mage/Core/Model/App.php(354): Extendware_EWPageCache_Controller_Override_Mage_Co re_Varien_Front->dispatch()
#7 /home/scentual/staging/app/Mage.php(683): Mage_Core_Model_App->run(Array)
#8 /home/scentual/staging/index.php(87): Mage::run('', 'store')
#9 {main}