When I try to join my friend dummikiller it keeps saying that his statistics and such may be because he is unavailable or having a network disruption, and even though it doesn’t let me join. Any help?
Is your NAT Open?
Sounds like incompatible network settings to me. Make sure both of you guys have open NATs and try again.
If its not Open just follow the guide over at xbox.com and support section to fix it.
http://support.xbox.com/sv-SE/xbox-live/connecting/nat-type-strict
I’ve written up a complete tutorial that will help solve you and your friend’s issue:
How To Improve YOUR Connection & Open NAT
Let me know if you have any questions.