You're starting at level 1, though, so a bead of karma is dead weight for your first 3 levels, and for your next 7 or so you only have, at most, a half-dozen spells. What's more, you have free reign to pick up items worth 200kgp, while a bead of karma is a mere 20k. This assumes you even go with Paladin casting, which may or may not be a good idea.
Anyway, Lockdown means using attacks of opportunity, tripping, and increasing your threatened area to basically keep everything in a large radius from doing anything. It's the 3.5e version of tanking, even though you yourself aren't going to be able to take much punishment for long.
DPS (or, rather, DPR), means dealing enough damage in a round to ensure that whatever it is you're attacking will absolutely die. It's typically done by getting a full attack after some kind of move (such as a charge, which you get with the Pounce ability, teleporting, called Shadow Pouncing, or somehow getting extra actions to move first and do your full attack later). As a Paladin, you're liable to want to do some mounted charging, which can be difficult, but is certainly not impossible.
I forgot, but there is also a casting route you can take. This actually demands that you start as a Cleric and then go into Prestige Paladin from UA. You get the same abilities, but a way better spell progression at the cost of some feat taxes.
