What hard drive for the xbox are you using.
I know a few people with the Thompsons hard drive that had problems connecting with certain servers on xbox live. they could only play a handful of games with the Thompsons drive. I'm one of the few people that have actually never had a problem with my Thompson's hard drive.
Are you capable of signing in on other games, if you are able to connect to other games without any problems it may just be the servers for that game and the way they communicate with your xbox or connection.
If you go to the forums on xbox.com there are plenty of people that can throw suggestions out to you.
1.2 Bearded dragons (Login, Raven, & Jean Grey) 1.1.1 Corn snakes(Havoc,Sable, & Kink0 1.5 Leo's (Psyloke (Lucky-male) Speedball, Domino, Rouge, Siren, Elektra) 1.0 Veiled Chams (Neo), 0.1 Rose Hair T. (Night Crawler) 0.0.3 Crested Geckos (Shiva, Storm, Beast) 0.2 Kenyan Sand Boas (Tigra & Cloak)