Obsolutely right!!! When I play Any CIV4 Games (Vanilla, Warlords or BtS) on my laptop ( 2.8GHZ, upgraded to 2GB Ram BUT ONLY 32MB Video Ram) I have to turn off the Videos and then go to Low Resolution/Detail to play the game. And still every now and then I get an error message that says there is not enough video memory.
So if you have the video on, try turning them off in the Options Menu. If they are off, try turning down the graphics details.