yeah i have the same problem.
i've got a dell dimension 4600
Pentium 4 @ 2.66 GH
512 RAM
Windows XP
ATI RADEON 9800
Direct X9.0c
and a Creative SB Live! Series sound card that is updated.
at first i thought it might've been the game running too slow for my graphics card, so i pulled the graphics detail level down, but still didnt help.
This thread is from beta 1.