CiviCRM Community Forums (archive)

Has anyone else experienced this issue?  

When I attempt to register a contact for an event I get the following error:
Sorry. A non-recoverable error has occurred.
We experienced an unexpected error. Please post a detailed description and the backtrace on the CiviCRM forums: http://forum.civicrm.org/

The error occurs when I attempt to register an event for a contact after I have already registered another.  It works for the first contact registration, but any subsequent contacts get this error.  I am not sure what triggers a 'reset' to allow the next one, but I usually have to logoff and wait a bit until it lets me put the next contact registration in.

Any assistance would be appreciated.

Here is the BackTrace:
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Core/Error.php, backtrace, 257
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Core/BAO/Discount.php, fatal, 129
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Event/Form/EventFees.php, findSet, 206
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Event/Form/Participant.php, setDefaultValues, 345
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Core/Form.php, preProcess, 315
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Core/QuickForm/Action/Upload.php, buildForm, 123
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/packages/HTML/QuickForm/Controller.php, perform, 203
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/packages/HTML/QuickForm/Page.php, handle, 103
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Core/Controller.php, handle, 263
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Event/Page/Tab.php, run, 107
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Event/Page/Tab.php, edit, 168
/home/<SiteName>/public_html/administrator/components/com_civicrm/civicrm/CRM/Core/Invoke.php, run, 215
/home/<SiteName>/public_html/administrator/components/com_civicrm/admin.civicrm.php, invoke, 72
/home/<SiteName>/public_html/administrator/components/com_civicrm/admin.civicrm.php, civicrm_invoke, 45
/home/<SiteName>/public_html/libraries/joomla/application/component/helper.php, require_once, 162
/home/<SiteName>/public_html/administrator/includes/application.php, renderComponent, 136
/home/<SiteName>/public_html/administrator/index.php, dispatch, 67
/home/<SiteName>/public_html/administrator/index2.php, include, 14