Crackdown 360 Live Problem

Everytime I start-up Crackdown (or GRAW), right before it asks me to donwload the update, it signs me out of Xbox Live. My Live account signs in when I turn on the console, but when I want to play Crackdown it signs out. When I choose 'Yes' it doesn't sign in again, it asks me to test my network connection. Does anyone have any ideas what can cause this? Without fixing this problem, I'll never be able to download the patch or play co-op or the beta online.

 

Just 10 minutes ago I updated Oblivion with no problem at all. But Crackdown still asks me to test my network connection when attempting to update.

 

Bump