Well I don't support Xbox's. I support computers so I can't tell you what the issue is. You might try a specific Xbox 360 forum or contact the manufacturer.
If your network was the issue, I could help you with it. But it doesn't appear you have a network problem.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.