While deleting host or triggers of some host, lots of errors generated, like given below.
But triggers and hosts disappears from the list, as should. This confuses very much, since looks like DB data after deletion is inconsistant.

• pg_query() [function.pg-query]: Query failed: ERROR: operator does not exist: character varying = integer at character 74 HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.[/var/www/zabbix/include/db.inc.php:293]
• Error in query [select distinct actionid from conditions where conditiontype=1 and value=10026] [ERROR: operator does not exist: character varying = integer at character 74 HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.]
• pg_fetch_array() expects parameter 1 to be resource, boolean given[/var/www/zabbix/include/db.inc.php:414]
• pg_query() [function.pg-query]: Query failed: ERROR: operator does not exist: character varying = integer at character 55 HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.[/var/www/zabbix/include/db.inc.php:374]
• Error in query [delete from conditions where conditiontype=1 and value=10026] [ERROR: operator does not exist: character varying = integer at character 55 HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.]