whoa. Hey man, as it's been pointed out already, the problem isn't DB/DBPro's fault (directplay), and you will never get that many players anyway. And if you really would be getting, I'm sure you would have figured out how to go around the problem.
And You can have 2000 active players, but who says they all are online at once? I mean, The amount of people online compared to the players you have is rather small usually in Online games. So the problem is very small considered to the problems you will have making the actual game, and getting it run. Oh, If you are thinking about making an MMORPG or anything with more than couple players, you would need a server for that. And getting a server is going to be a much bigger problem than going around the max. 255 players.
Hope I didn't upset you by just repeating what rich and Froggermon SSE said, but I sometimes lose my nerves because of this. sorry.
Specs :: [1333Mhz : 256DDR : Geforce 2 Mx 64MB]