How do i use one of my PS3 games?

Sounds about usual. You won't be able to LLE cellGcm, as it interfaces directly with the hardware.

So does that mean this game is unplayable right now? Strange, its so old.

Not sure why you'd think that the age of the game would matter.
As mentioned before, read the newcomer's guide and see the list of playable games.
For all games that I can think of, you're better off playing on a real PS3. Playing them on an emulator currently is just more of a hassle.