Is there a point in the game, that anybody caught, in which you determine your ending? The point at which you decide if you will receive the light or dark ending?

 

The point in KotOR was at the top of the spire on the Unknown World. No matter how good or evil you where, you could turn it around at that point -- which really made all your previous light/dark decisions meaningless.

 

If there is a point like that in KotOR2 I'd like to find it and get a save point just before it, so I can work with some dialog between the two paths. Maybe something, somewhere, will help explain some of the larger plot holes I am still having trouble with.

It could be a combination of things this time around, but I don't know. I played as Jedi throughout the entire game - I never gained Dark Side points, ever. Possibly your choice to kill Kreia outright or to spare her life at the core? Killing off the Jedi Masters? It could just be your alignment at the end of the game.