Hm, very odd indeed.
Well, first off would be the obligatory patch question, and I know you already said you don't have any patches installed, but just have to make triple-sure. No roster patches, not one single graphics patch? Okay, then.
Second, clear your temporary internet files. In older versions of live, this worked absolute wonders for me, not just during saving, but once it also somehow fixed the problem of the names on my jerseys not appearing. <shrug>
Third, download, install, and run these two programs, if you don't have them already.
http://www.lavasoft.de/software/adaware/
http://www.download.com/Spybot-Search-D ... 22137.html
Spyware can 'piggyback' onto any program on your computer, and crash it as a cover for it 'connecting'. I don't fully understand it, but these stupid spyware hacker people are amazing.
Also run whatever virus scanner you have, if you don't have one, there's a free one available here:
http://www.download.com/AVG-Anti-Virus- ... 20142.html
It's not great, but it's far better than nothing, if nothing is what you have.
Also, either updating or rolling back your video/audio drivers might help.