I always get the message SNMP Traps can't be rxed on port ..

Hi
I am using Win XP with SP1 on Dell D 600 Laptop with 512MB RAM & other specs.
I installed OpMgr 5. When I run Opmgr 5, I get teh following message :-

1. SNMP Traps can't be rxed on port 162. Free the port or Stop the SNMP Trap service & Restart the server again.

I have disabled teh SNMP Trap setting in teh Services under Computer Mgt. Still the above error persists. I am unable to run OpMgr5.

I got the similar erro for Port 80 but could change it to Port 9000 & Port 8009 to port 9001.
Q. How do I change/stop the posrt 162 from being used so that OpMgr can use it.
Also Why Op Mgr5 asks so many questions abt ports for installation. Can u not make it intelligent enough to decide teh free ports for a smooth installation?

Pls revert asap as I am unable to try out OpMgr 5