the stats server is down. You can find you're own by typing your name in the player name search box...

Try sorting the stats by 'last date played' to see when the last stats were recorded. If its out by 24 hours or so you know the stats server is down (happens quite frequently). If the stats are recording but yours aren't showing, then you've been playing on a server that doesn't have punkbuster running. No punkbuster = no stats.

Bite my shiny metal Tie Fighter!