Following are error message appearing on Configuration>Maintainances page of Zabbix GUI:

• Error in query [ SELECT mmg.maintenanceid FROM maintenances_groups mmg WHERE (mmg.groupid IN (4)) ] [Table 'zabbix.maintenances_groups' doesn't exist
• mysql_fetch_assoc() expects parameter 1 to be resource, boolean given[/var/www/html/include/db.inc.php:546]
• mysql_free_result() expects parameter 1 to be resource, boolean given[/var/www/html/include/db.inc.php:548]
• Error in query [ SELECT mmh.maintenanceid FROM maintenances_hosts mmh, hosts_groups hg WHERE hg.hostid=mmh.hostid AND (hg.groupid IN (4)) ] [Table 'zabbix.maintenances_hosts' doesn't exist]
• mysql_fetch_assoc() expects parameter 1 to be resource, boolean given[/var/www/html/include/db.inc.php:546]
• mysql_free_result() expects parameter 1 to be resource, boolean given[/var/www/html/include/db.inc.php:548]
• Error in query [SELECT DISTINCT m.* FROM maintenances m WHERE ((m.maintenanceid BETWEEN 000000000000000 AND 099999999999999)) AND (m.maintenanceid IN (-1)) ORDER BY m.name ASC LIMIT 1001 OFFSET 0] [Table 'zabbix.maintenances' doesn't exist]
• mysql_fetch_assoc() expects parameter 1 to be resource, boolean given[/var/www/html/include/db.inc.php:546]
• mysql_free_result() expects parameter 1 to be resource, boolean given[/var/www/html/include/db.inc.php:548]

I am not getting values update since i have upgraded zabbix from 1.6 to 1.8.