Faint horizontal line on plasma screen when running Xbox 360 with components...help!

Hi,

I have a 42" Samsung Plasma and I'm running an Xbox 360 to it with the supplied components leads. The lead has been set to 'HDTV' on the switch and the Xbox has been set to '1080i'. The picture and sound are great apart from one thing.....

Across the screen I am getting a very faint line, approx 7mm in height. The line doesn't move, it sits a third of the way down the screen. This line only really stands out when I'm watching hd dvd's on the Xbox HD DVD drive, especially when the picture is showing grey...an example is a dusk setting.

It is there when I play games also but you will never notice it! Maybe only on a loading screen or something when the picture is static.

At first I thought it might be the Plasma screen....maybe screen burn or something but I have Sky connected through a scart and a DVD player connected through HDMI and they are both fine.

Firstly, has anyone else had this before???

Secondly, does anyone know how to slove the problem?

I am concidering purchasing the 'Monster' components lead for the xbox 360 as an upgrade to see if this will solve the problem, but as you could imagine it's an expensive lead (£50) and might not make a difference!!

So help if you can.........cheers