CiviCRM Community Forums (archive)

Recently upgraded from CiviCRM 4.0 to 4.1.5, then to 4.2.6 along with upgrade from Joomla 1.6 to 2.5.6 to 2.5.8.  Also migrated, following all the instructions re clearing cache and updating settings, but have a persistent problem.

When registering for events or membership, we've received dozens of reports of members who get a blank screen after entering their information instead of the confirmation screen.  Nothing shows up in Apache, and a white screen appears if I have debugging turned off.  With it turned on, the following backtrace is displayed:

#0 /home/XXX/XXX/administrator/components/com_civicrm/civicrm/CRM/Core/Error.php(305): CRM_Core_Error::backtrace()
#1 /home/XXX/XXX/administrator/components/com_civicrm/civicrm/CRM/Core/Controller.php(251): CRM_Core_Error::fatal("We can't load the requested web page. This page requires cookies to be enable...")
#2 /home/XXX/XXX/administrator/components/com_civicrm/civicrm/CRM/Core/Controller.php(160): CRM_Core_Controller->key("CRM_Event_Controller_Registration", TRUE, FALSE)
#3 /home/XXX/XXX/administrator/components/com_civicrm/civicrm/CRM/Event/Controller/Registration.php(41): CRM_Core_Controller->__construct("Event Registration", "null")
#4 /home/XXX/XXX/administrator/components/com_civicrm/civicrm/CRM/Core/Invoke.php(207) : eval()'d code(1): CRM_Event_Controller_Registration->__construct("Event Registration", TRUE, "null", NULL, "false")
#5 /home/XXX/XXX/administrator/components/com_civicrm/civicrm/CRM/Core/Invoke.php(207): eval()
#6 /home/XXX/XXX/components/com_civicrm/civicrm.php(78): CRM_Core_Invoke::invoke((Array:3))
#7 /home/XXX/XXX/components/com_civicrm/civicrm.php(18): civicrm_invoke()
#8 /home/XXX/XXX/libraries/joomla/application/component/helper.php(383): require_once("/home/XXX/XXX/components/com_civicrm/civicrm.php")
#9 /home/XXX/XXX/libraries/joomla/application/component/helper.php(351): JComponentHelper::executeComponent("/home/XXX/XXX/components/com_civicrm/civicrm.php")
#10 /home/XXX/XXX/includes/application.php(197): JComponentHelper::renderComponent("com_civicrm")
#11 /home/XXX/XXX/index.php(42): JSite->dispatch()
#12 {main}

If nothing else, I at least want an appropriate error to appear instead of a whitescreen or backtrace. Any  help would be most appreciated!