ABS light on 99 b4000

Quick question- My ABS light has been coming on.
Here's how it goes. If I am driving, and say, approaching a red-light, and begin to slow, and then if the light turns green right as I get there, so I begin to accelrate, well, my EMERGENCY BRAKE light will come on briefly- 2 seconds or so.

Then, the EMERGENCY BRAKE light will go off, and the ABS light will come on. The ABS light will then stay on until I turn my vehicle off.

As I mentioned, this only happens when I don't make complete stops.
The brakes seem to be reacting fine- I have noticed no noises or odd feelings.
I just changed the pads and the rotors a few months ago, so it doesn't seem like this would be the problem.

Any ideas?
Thoughts?

Thanks in advance.