HELP!!! 2007 Prius RED Triangle & yellow exclamation point in a circle

Ive read some similar posts but I havent found one with the same problem.

I have a 2007 Toyota prius base model, it has 49,845 miles.
Today i got in, pressed the bake, pressed the on button, and the Red Triangle appeared with yellow exclamation point in a circle, and on the lcd monitor it shows that there is a problem anda little icon of a car with an exclamation point on it.

The car drives and runs normals, fuel mileage seems to be the same, everything looks normal except the lights.

HELP!!!!!!!!!!!! does anyone have any ideas of what this means?
one thing i tried to do: i took off the battery clamp and i put it back on, the warnign lights were gone, but as soon as the engine kicked in the same warning lights came on.

I would appreciate if someone helped me on this one!