ABS and new brake system

Can anyone tell me if I just spent $1070.00 on a brake job why the ABS light just came on. It comes on after I drive on the highway for a while. Could there be another problem with the brakes and should I take it back?

For that amount of coin I'd surely think the people that performed the work would back it up with a warranty of some sort. That's one pricy brake job or am I just out of sync?