More about Analytics:
Here's a few threads
1 - http://www.google.com/support/forum/p/Google+Analytics/thread?tid=664650961d4e8600&hl=en
2 - http://www.google.com/support/forum/p/Google+Analytics/thread?tid=21c2e29cbb6f5e59&hl=en
3 - http://www.google.com/support/forum/p/Google+Analytics/thread?tid=27973e157dc95ad1&hl=en
You can pop open a few of these threads and see others around the world have problems everyday.
The problem with Google Analytics is that it's free, therefor they don't fully put everything into it. There's no real support as well, because it's free.
The system for tracking data goes out everyday, here and there. Some people get hit for days, some never get hit. It's like a hit and miss thing.