I had similar issues - it gave me the message that the game was unable to save stats for my profile. That and the "you must download the most recent season of TH" happened when I moved my profile to a jump drive. Moving it back to the hard drive seems to have helped eliminate those issues.
Started Using x360a.org - June 2008 - 3K Gamerscore
Hit 100,000 GS on 12/22/2011 with Mile High Club - thanks to all the boosters and this great site.
Looking to Boost: Bioshock 2, Ghostbusters, Quantum of Solace, GTA IV Multiplayer, Halo Reach DLC
Message me on XBox Live if you need an extra player for any of those.