CMDPHP Poller[0] ERROR

[asasul]

Do any one know why my cacti giving error everyday at a specific time ..Errors are as follows ....

02/05/2008 04:00:02 AM - CMDPHP: Poller[0] Host[6] DS[171] WARNING: Result from SNMP not valid. Partial Result:
02/05/2008 04:00:40 AM - SYSTEM STATS: Time:38.3146 Method:cmd.php Processes:1 Threads:N/A Hosts:83 HostsPerProcess:83 DataSources:432 RRDsProcessed:186

02/05/2008 04:05:06 AM - CMDPHP: Poller[0] ERROR: SQL Exec Failed "truncate table poller_time"
02/05/2008 04:05:07 AM - CMDPHP: Poller[0] ERROR: SQL Assoc Failed "select poller_id,end_time from poller_time where poller_id = 0"
02/05/2008 04:05:08 AM - CMDPHP: Poller[0] ERROR: SQL Assoc Failed "select poller_id,end_time from poller_time where poller_id = 0"


every time atfer 10 mins it come back ..i already confirm that there is no more cron job then one for cacti ....