Video Problem - No red spectrum in 720p format

I have a pioneer plasma pdp-505cmx with pda-5004 video card installed.

I am using component video cables running from the cable box, to my receiver, and then from the receiver to the display. Oddly enough, when I select a progressive format on the cable box, I get only greens and blues in the picture, but when selecting an interlaced format, I get the full spectrum of color.

I've tested the cables I'm using, as well as the outputs on the receiver and box. Clearly, since I get full color on 1080i, the connections are secure.
Does this sound like a problem with the TV or with the cable box? It may be important to note that if I use a DVI to HDMI cable from the display to the cable box directly, I get full spectrum in any format.

For what it is worth I have RCN cable, and their latest Motorola (its black with blue backlights) cable box.
Make sure your component input is set for component and not RGB(computer)
i agree with rwwear--the setting on your display is most likely set to rgb (or to interlaced) rather than component (or to progressive)--use your tv remote to correct. you can try running the component out on your cable box directly to the display to see if in fact this is the case. my question is why not use the hdmi output on your receiver (or, if doesn't have one, run hdmi directly from cable box to display. you'll most likely get a better picture than through the component out.