problem with flashing lights

in the new animation i am trying to make, i have used keyframes to animate the camera moving through a room. however, when i rendered it with blender and yafray, blender added random camera movement that i hadnt set as keyframes.
it also made lights flash, even though the lights in the scene dont move at all.
whats going on?

As far as the camera goes, look in your IPO graph. By default, Blender attempts to smooth out a keyframed path by using Bezier curves. Often, however, this can lead to undesirable results. You can either select the camera, go into the IPO window, select the curves that show motion and change the interpolation mode to “Linear,” or, when you are in the IPO window, press TAB to enter the edit mode for the curves. From here, you can manually adjust the bezier curves to give the camera the path that you want. This may or may not be your problem.
For your lights, check your IPO window just to make sure that you did not accidentally give them some keyframes. Also, check to make sure that they are not too close to another object. If they are very close to something like a wall, it could cause Blender to make them flash depending on the angle from which you view them.

Also check that you have sufficient Dist(ance) settings on both the camera and the lights. I don’t know if, or how, these settings are sent to Yafray.