Good effort, now expand it!
I know quite a bit of Actionscript myself, but I think making the computer AI just the right level, as you have here, would take me some time, so, if I were to make this same Pong game, it would've taken a reasonable effort.
Assuming it took you a reasonable effort as well, I've voted in your favour, as there's really nothing wrong with the game.
Now that you've succeeded in scripting the game adequately, you should expand it with sounds, two-player mode [this should be like five minutes work at this stage], animations [think of small animations when someone scores, or subtle bending of the 'paddles' when the ball hits, etcetera], levels and some nice art.
You know, some things to make it special and to make it stand out against the hundred of other Pong games on the Internet / Newgrounds :)
Good luck!