I have a CentOS 5.2 x86 machine running Cacti latest... after many many errors from the software and from me as well

Anyway, I have graphs for the local machine and I need to add a Win XP x86 machine for monitoring.
I configured SNMP on it correctly but the thing is that the graphs for it won't generate if I have the Windows Firewall enable.
I enabled port 23 for UDP ping and port 161 - which is the port for SNMP, but without luck.
If I turn completely off the firewall, then it works!

Note that those ports are enabled only for subnet network only (since both cacti and XP are on the same subnet).
I've looked all around the forum but couldn't find anyone with this problem.
Later Edits: for port 161 I added it both for TCP and UDP.
The SNMP agent is also configured to allow connections only from the cacti server.
I also allowed c:\windows......\snmp.exe but still nothing

Thanks!
Chris