[Hiro]

from what i've found you essentially have to do the follow procedures in order to make UDP work (on vista):

1) start menu> run > cmd
type in "ipconfig /all" and look at what it tells you for the connection you use for the internet. make sure you know the "IPv4" address, the "default gateway" and "domain name service" numbers
2) open your network connections and go into the properties of that connection. you want to edit the IPv4 connection settings with the ones you obtained in cmd. this sets your computer a static ID
3) open your network and go to your routers admin web page and ensure that you DNS servers are set up properly on the page, as i've found that just having it correct on the computer isn't enough sometimes.
4) go to "virtual servers" and add a new port to be forwarded. you want to forward "14899" through both TCP & UDP: name it "graal" or something, and set the IP to your static address you set earlier for IPv4
5) log on graal and press f3 for options. go to the "general" tab. check "use fixed port for UDP" it should be 14899 by default. then uncheck "don't use UDP for data packages" and restart graal

this usually fixes the problem, though i haven't tried it on wireless connections. you can also go back to your router web page and enable your router as a demilitarized zone (DMZ) so that all ports are open all the time, but this hasn't proven to me to fix UDP all the time. i've also found that using the "PFPortChecker" program and asking it to check that port 14899 is open for UDP before opening graal seems to prove to my router and computer and the graal servers that its open, and then i can see everyone move. if i don't do that, i usually end up seeing everyone but some people cannot see me unless they reconnect (which no one wants to do)