Omeka Has Encountered an Error

Zend_Session::start() - /opt/Apache2/htdocs/global_health/application/libraries/Zend/Session.php(Line:479): Error #2 session_start() [function.session-start]: open(/var/lib/php/session/sess_2ch3n18ouga8i09dldikeeohf5, O_RDWR) failed: Permission denied (13) Array /opt/Apache2/htdocs/global_health/application/libraries/Zend/Session.php(Line:489): Error #2 session_write_close() [function.session-write-close]: open(/var/lib/php/session/sess_2ch3n18ouga8i09dldikeeohf5, O_RDWR) failed: Permission denied (13) Array /opt/Apache2/htdocs/global_health/application/libraries/Zend/Session.php(Line:489): Error #2 session_write_close() [function.session-write-close]: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/lib/php/session) Array