Halo 2 Vista Video-linked Online problems

Hey guys, I've been playing Halo 2 Vista since it's release and playing online has not been a problem for me at all, I've got all the required ports opened so I can play well. Only recently, about a week ago I tried joining a dedicated server on the list provided. I enter it, the usual, I get the big HALO 2 loading thing with the blue light going across the letters, the screen goes black, and a message displays "Please Wait Setting up game..." and then "Please Wait Connecting to the session...". The screen goes black, I can hear the sound effects such as the distant gunfire in District, or the train in Terminal, and then it goes back to those two messages. After around 6 to 7 cycles of this message, out pops "We're experiencing some problems at the moment, Sorry about that." Is there a particular reason why this is happening?

I'm not sure if this is of any relevance too, but when I'm playing campaign, if I press escape to pause the game, there's about a 7 second time delay for it to get to the pause menu, or I'll have to alt-tab my way out and then back in. Sometimes while doing that my screen starts flickering black on and off, and I must alt-tab again so that disappears. My video options atm are 1280x1024 - 60hz refresh rate, 4 - sample AA, high level of detail.

Please, could someone help me out? I'd like to thank anyone in advance that does.

I'm not too sure, it could be that LIVE went down, you were just having network troubles at that moment, or that server was set to invite only or closed.

Nope, it's been like this for 3 weeks now.

Did something to your vista about 3 weeks ago?

Nothing to Vista, and the ping is very low, I only join 3 barred servers.. so I don't know. Cable is fine, so I THINK that it has to do with the video.