Good morning and thank you for posting on the Final Fantasy XIV Technical Support Forums.

I will have to agree with the above poster. Try to change to DirectX 9 mode (This can be done on the launcher under 'config'). You can also try updating you graphics card drivers to the most recent version.

When exactly do you receive this error? Is this only during a Raid, or can it happen at any time?

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!