Halo 3 only saves/loads and allows achievements while connected to Xbox Live, Help?

[MossyStump]

After days of frustration trying to figure out why I couldn't save/load on Halo 3, I found out that I can ONLY do it if I'm connected online, while that shouldn't be a problem normally, I don't have a long ethernet cable at this time so it is highly inconvenient to be connected unless I move my television and xbox right next to my router.
So my actual question, is there a way to counter this so I can play and save while not connected?
The first time I played Halo 3 with my GamerTag was when I WAS connected to Xbox Live, and the game updated upon connecting, I do not own any dlc
I just recently got my Xbox. I originally had a profile on it, but wiped my harddrive and went online and created my xbox live account before adding it to my xbox, at which time I started playing Halo 3 again. Previous to adding my xbl account, I could play fine with my normal game profile

 

[young 4ever]

have you replaced your console recently, like maybe it got repaired or you got a new one?

if so, and if you bought DLC for Halo3 on an old console, that is why you must be connected to xbox live for it to work.

since the DLC was linked to your gamertag and your console, it will work while your gamertag is online with a new console, but not if you are offline with a new console....