Modern Warfare 2 Stimulus Pack Is Live But With Defect

The following is the status update from Kotaku regarding the Modern Warfare 2 Stimulus Pack:

Update: The pack is now working.

Update 2: Now it appears that marchmaking isn't working on Xbox Live. Larry Hryb writes that the service is in a "bad state" right now and they're working quickly to resolve it.

Update 3: Microsoft's official support page is reporting that the map packs still aren't working and lists a slew of other things that Xbox Live users can't currently do:
Creating new Xbox LIVE accounts, managing those accounts, or recovering an account on a different console
Buying downloadable items from the Xbox 360 console, Xbox.com, or Games for Windows – LIVE
Paying for downloadable items with a credit card
Signing into Games for Windows – LIVE on a PC
Redeeming downloadable items with Microsoft Points, buying additional Microsoft Points, or viewing your points balance
Using prepaid cards or codes for downloadable items or Xbox LIVE subscriptions
Purchase transactions using the Games for Windows LIVE client.

Update 4: Modern Warfare 2 DLC is up and running. Live status is still suffering issues.