x3 tire warning light won't go out
 

I have an X3 (2006 - no i-drive) and the tire warning light came on last night; this morning we saw the tire was flat. Took it to a tire shop, and the repaired the tire. The light is still on - we checked all the tire's pressures, and all are fine. What now? There is a sticked on the driver side door that says reset with a code - is this something I can do? Help!