Result from SNMP not valid. Partial Result: U

[pp2011]

I intstall the cacti on windows 2003,and Monitor other server(windows2003),now.It can catch traffic data only,can not get other's data,etc,cpu,memery.
I use mrtg monitor the server,It can get the data.
At the cacti console-Devices-Host Template i choose ucd/net snmp host.
The cacti'log :
02/26/2011 06:54:17 AM - SYSTEM STATS: Time:14.9706 Method:cmd.php Processes:1 Threads:N/A Hosts:3 HostsPerProcess:3 DataSources:27 RRDsProcessed:19
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] Host[3] DS[16] WARNING: Result from SNMP not valid. Partial Result: U
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] WARNING: SNMP Get Timeout for Host:'172.16.20.100', and OID:'.1.3.6.1.4.1.2021.4.6.0'
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] Host[3] DS[15] WARNING: Result from SNMP not valid. Partial Result: U
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] WARNING: SNMP Get Timeout for Host:'172.16.20.100', and OID:'.1.3.6.1.4.1.2021.4.15.0'
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] Host[3] DS[14] WARNING: Result from SNMP not valid. Partial Result: U
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] WARNING: SNMP Get Timeout for Host:'172.16.20.100', and OID:'.1.3.6.1.4.1.2021.4.14.0'
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] Host[3] DS[13] WARNING: Result from SNMP not valid. Partial Result: U
02/26/2011 06:54:11 AM - CMDPHP: Poller[0] WARNING: SNMP Get Timeout for Host:'172.16.20.100', and OID:'.1.3.6.1.4.1.2021.10.1.3.2'
I need help.can you help me?

[BSOD2600]

1) read/follow http://forums.cacti.net/viewtopic.php?f=3&t=11747 and then repost your findings.
2) delete the default LINUX device that comes with cacti. create a new device using the WINDOWS host template.