NFSU: PS2 Online Uknown Error

when i try to log in, i get an unknown error has occurred. Anyone know why this is happening? also, i just bought the network adapter today. i connected the adapter to the ps2, then used the cord to the Router. currently i'm online using the router with the computer. I tried the demo madden 2003 n' it works online. Not sure why i'm getting an error with NFSU though.