Known problem with lightmaps. You need to relight the map (do a search to find out how! It's also alluded to in the PSClientCMD part of the Guide). Relighting the map can take HOURS, so you may think your game has frozen: it probably hasn't. It's not that big a deal, though. Unless you're really bothered by it, don't worry. Anyway, since this is a known issue... iLock.
