Sony has told Eurogamer that Killzone 2 multiplayer servers are not active, and won't be until sometime close to its launch on 27th February.
Thus, the pre-release promotional copies currently out there will not work online until servers are up and running. There's nothing wrong with the discs themselves.
The platform holder was speaking after reports of Killzone 2 promotional copies not working online popped up on the official US PlayStation forum.
Promotional copies are distributed before release to industry insiders. They often end up on eBay, fetching sky-high prices from eager fans.
Both Xbox 360 and PS3 promos come without a manual or any disc-art, but otherwise are identical to regular retail games. The words "promo only - not for resale" are also clearly printed on the discs.
Killzone 2 will be released exclusively for PS3 from 27th February. There's a PSN demo to be tried until then.