Traction Control Light On problems of the 2006 Toyota Prius

I have noticed that while driving my 2006 Prius, that while traveling over an uneven road surface or pothole, there are times where the traction control light will come on, on the dash, while simultaneously, it feels as if the car is uncontrollable. Its a similar feeling as driving on a snow covered surface. Not sure if its just a flaw in the traction control system (may include a braking issue as well). I did contact my local dealer, who was not familiar with this issue, yet if you were to do a search online, you will see that other Prius owners have experienced this as well.

1. Brakes on my 2006 Prius momentarily failed to respond, after a 1 - 2 sec delay they activated. At same time,the traction light flashes, but the car is not losing traction. This happened 4 x, one almost resulted in a crash. It is more likely to happen when braking while going over a bump in the road. There have been other times when the traction light flashes on unexpectedly, but effect on brakes is unknown: not braking then. 3 different Toyota dealers told me they couldn't find anything wrong. At one dealer, I went for a test drive with a mechanic. During the test drive, I was able to make the traction light go on when there was no loss of traction. The invoice stated "test drove and checked operations. At this time could not duplicate customer's concerns. " I wrote on the invoice "I was able to make the traction light go on when there was no loss of traction. I am not satisfied that the problem has been found and repaired. " & on the signature line "not satisfied, (signature)" I wanted them to change the computer, but they said if they couldn't duplicate the problem, they couldn't change the computer. I insisted that they replace one component, and if the problem didn't reoccur, I'd know they found the solution. They bled the brakes, which was unlikely to be cause of the problem. When I went to pick up my invoice up 2nd time, the copy on which I had written my comments was returned to me, and a freshly printed copy- without my comments - was given to me & kept for their records. 2. Same car: headlight go out at unexpected times. 2 Toyota dealers told me that the bulb would cost $300, and installation would be well over $100 because they "had to take off the bumper to change the bulb!" I replaced the bulb myself (without taking off the bumper) but now, 9 months later, it is starting to go again. Toyota sent a letter saying it was how hid bulbs burned out & not a pblm w/ controller. If true, how is it that new bulb is also burning out?.