Probably the same problem a lot of New Beetle owners have - there is a cable running under the seat to the setabelt clasp and if it gets severed or shorted or the wires in the clasp get damaged, the airbag light comes on. You need a VAG reader (obdii) to check and the error code is 00591. I am trying to fix mine as VW will replace at $250+. You need a VAG reader to clear the code too. I got one for $35 + shipping on Amazon as I couldn't find one on Ebay.
If its something else, new airbags cost $500 and up
PS I would normally have gone to the dealer but I just spent $700 on some other repairs and a service so I'm looking for a cheap way out if I can
i work for volkswagen and with these beetles we usually find that the seat belt buckle attatched to the seat are crap. but once replaced they're ok cuz they updated them. thats the most common. then theres the pods system in the rear seats, than the crash sensors in the front of the vehicle. but definitely take it to the dealer, dont wanna be throwing parts at it, specially dealing with airbags.
ok long and short , it could be the butt connectors under the seats , ususlly doing both, however some of these beetles to have problem with the front crash sensor...check woth your dealer they are under recall .. i work for vdub service in miami...do some work on the side...email me if you can get help and i will run your vin thru vdub site and check if you have recalls...thanks and good luck ...vdubs are really #1 ....mike