The only real issue is that the servers we're getting hit really hard, especially with the launch in Europe doubling that traffic, just something that requires optimising on the server side and we've been working with the PSN COD4 Server team from the moment it started having issues assisting any way we can to help them get them up to speed faster."
In an update this morning, Infinity Ward said they're "upgrading all server hardware as well as dedicated an individual database to each functionality to improve performance and handle the traffic hitting the servers. (i.e. Database for Matchmaking, Database for Leaderboards," which should lead to smoother play for eager gamers.
"During this upgrade you may still receive the 'Downloading Game Settings' message, but it is temporary, in the sense of just let it download and you will eventually drop into a lobby and play just fine," it explains.
"Remember, this is just short term, eventually once everything is upgraded you won't be receiving Downloading Game Settings at all. However, if you do, just wait it out and you will be dropped into a lobby."