my airbag light came on yesterday and hasnt gone out any sugestions???

<img src="http://pictureposter.audiworld.com/148281/2003_silver_bullit.jpg
1/2003_silver_bullit.jpg

2003 A6 4.2 liter quattro
Silver Bullit
Clear Bra
APR chip- 350hp
Cold weather package
Sport package
K&N Air filter ( Swiss cheese air intake)drilled about 100 holes in the intake tube. Makes a great sound when you mash it and great engine response. When I turn my car on it returns the favor!
Have ran it up to 145MPH so far. I want to see what 160MPH feels like