Omeka has encountered an error

Zend_Session_Exception

Unable to set session handler

Zend_Session_Exception: Unable to set session handler in /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Session.php:287
Stack trace:
#0 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Resource/Session.php(116): Zend_Session::setSaveHandler(Object(Omeka_Session_SaveHandler_DbTable))
#1 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application/Resource/Session.php(22): Zend_Application_Resource_Session->init()
#2 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(695): Omeka_Application_Resource_Session->init()
#3 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(641): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('Session')
#4 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(598): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap('Session')
#5 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application/Resource/Auth.php(23): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap('Session')
#6 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(695): Omeka_Application_Resource_Auth->init()
#7 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(641): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('Auth')
#8 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(598): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap('Auth')
#9 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application/Resource/Currentuser.php(26): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap('Auth')
#10 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(695): Omeka_Application_Resource_Currentuser->init()
#11 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(641): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('Currentuser')
#12 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(598): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap('Currentuser')
#13 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application/Resource/Helpers.php(116): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap('Currentuser')
#14 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application/Resource/Helpers.php(27): Omeka_Application_Resource_Helpers->_initAclHelper()
#15 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(695): Omeka_Application_Resource_Helpers->init()
#16 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(641): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('Helpers')
#17 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(598): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap('Helpers')
#18 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application/Resource/Frontcontroller.php(63): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap('Helpers')
#19 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(695): Omeka_Application_Resource_Frontcontroller->init()
#20 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(638): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('frontcontroller')
#21 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application/Bootstrap/BootstrapAbstract.php(598): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap('frontcontroller')
#22 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Zend/Application.php(373): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap(NULL)
#23 /home/sharonml/public_html/digitalpublichistory.org/application/libraries/Omeka/Application.php(49): Zend_Application->bootstrap()
#24 /home/sharonml/public_html/digitalpublichistory.org/index.php(23): Omeka_Application->initialize()
#25 {main}