The variety in this game looks utterly insane. Vehicles, Missions, Characters, Landscapes, Guns - everything. I can tell i'm going to sink a ton of hours into the online if it hits PC. Probably won't go for an awful lot online on the 360, though.
Are you running custom firmware or anything? This is the first thing that comes to mind. If you are look up the issue on XDA - developers. The other thing is to make sure you have a good quality brand of SD card such as sandisk - you can get these dead cheap off amazon these days. Failing this (ie, if your software is stock and so forth) submit a support ticket with samsung and i'm sure they'll help you out.
Edit: holy shit it's kel, name changes confused me, how you goin' man?
There should be a button for it you can define in the controls menu, it'll be called 'skip user tracks' - off the top of my head i think T does it, but don't quote me on that.
Edit: If T doesn't work, the internet tells me [F5] should.