Not showing an Energy keyframe?

I am trying to make a light flash on and off, but the keyframe for “energy” is not showing (i am using blender 2.57)

Please bear with me, as this is my first post!

You seems as desperate as me with the 2.57 version…
Well, do as me, try every trick you know…in this case, place the mouse cursor over the “Ener:” value box and pres I key!
An “Energy” key will appear in the…ah, “Dope Sheet” or…ah, F-Curve Editor!
Bye and be brave

Update it to the latest version! Or you may find the related tool to do you a favor!

if you hover over the energy value and right-click you can select insert keyframe.