It appears that the Forza Motorsport 3 Community Choice Classics DLC pack had ‘some collision issues in multiplayer’. As a result Turn 10 have fixed the problem, and are now requesting gamers delete the Community Pack from your hard drive and re-download the pack via your download history.
To do this, here’s the instructions:
Deleting the Pack
1) From the Dashboard, go to My Xbox then scroll over to System Settings.
2) Select Memory then select the storage device in which your DLC is saved, usually this is the Hard Drive.
3) Select Games, and then scroll till you find Forza Motorsport 3.Here you will see your entire save information, the only content item you want to delete here is the Community Pack.
4) Scroll down to the Community Pack and select it by hitting the “A” button.
5) Once selected you will see the Delete option, delete that pack from your Hard Drive and only that pack.
6) Exit back to the Dashboard.
Re-downloading the fixed Forza Motorsport 3 Community Pack
1) From the Dashboard go to My Xbox, scroll over to the profile blade; this will have your Gamerscore and Avatar in front.
2) Hit the “A” button on the profile blade to bring up your profile information. Scroll over to the Account Management blade and select Manage Account. Inside the Manage Account screen you will see your Download History. Once you select the Download History you will be brought to a screen which list all of your content downloads from Xbox LIVE Marketplace,
3) Scroll through your history to find the Community Choice Classics Pack then select the pack by hitting the “A” button and choose to Download Again.