Problem: Green only on Infocus SP5000 when viewing HDTV

Hi all-

We recently purchased an InFocus Screenplay SP5000 LCD projector. It is connected to a Comcast-branded Motorola HDTV-capable cable box (can't discern the model number of the cable box by looking at it). The cable box is connected to the project via component cables. When viewing standard-definition program material, the picture is just fine. However, when we try to view HD programming, only the green portion of the picture shows up, and there is a blank band on the right side of the screen. I have tried using a different cable, and this does not help. And I know that the cables are hooked to the correct colors, confirmed by the fact that the standard definition programming looks perfect. The projector is also working just fine when connected to the DVD player via component.

Any ideas why this might be happening?

Any help would be greatly appreciated!

Best regards,
Eli