look at my sig, 7900GTX, I also tried it on my server (3500+/6800GT/1gig) with the same results.
My server install has 0 tweaks, but it does force aniso, I'll try without, thanks. (I wanted to throw it up in my =COOP=SRV in HL.) :)
UPDATE:
So the problem here is ANISOTROPIC FILTERING...
wtf lol, I turned it off, and sure enough, it starts with no problems whatsoever... (I guess it s down to the weather/AF combination) a LockOn bug perhaps with texture filtering?
Thanks for the heads up. Problem is, clients trying to join with anisotropic filterin enabled will CTD :(