There's 2-3 locations in silent valley where you basically get stuck. No visible obstacles just plain field but you are unable to move. Happened to me and 3-4 other people today while doing the quest there.
PS one of them is just to left of the ramp you go down to from the tp point
would you believe this is the first time I m killing mobs in SV? I just always thought of it as 10101010 place and even when I was in the right level range I never went there :S
But meh, it's annoying getting stuck on geodata with 49/50 q items :S