Personally I never had this problem. I wonder if the latest AO patch changing the way some things are rendered fixed the issue and thus ATI consider if "fixed" .Issues Resolved in Catalyst® Software Suite 6.10
Anarchy-Online: Screen corruption is no longer noticed when walking or running through the terrain. Further details can be found in topic number 737-22016
Or now that they finally fixed this issue.... it breaks the new AO patch on ATI cards lol.