Cant connect to PSU

For days i have been unable to connect to psu and i dont know why. ill start the game and it will just disconnect after attempting to connect after a few seconds. i have a netgear router but i dont have any other problems with anything else, i can log on FFXI, DC Universe online, surf the web everything, psu is the only game i cant connect to, anyone have any idea why this is happening?

Im on windows xp home, using a netgear WGT624 V3 wireless router, connected to a ZyXel P-600 series DSL modem connected by ethernet no usb. provided by Earthlink modem is bridged with router to allow NAT TYPE 2. as i said before PSU is the only game i cant connect to everything else is fine.

Go to Start, Run, firewall.cpl, and make sure that PSU is not being blocked.

Im on xbox 360 but i checked and nope its not being blocked at all.

i wish someone would answer this. i am having the same problem