I am seeing vertical lines in my Panasonic TH-50PHW30 plasma picture, mainly in red or yellow sections when I use my Nokia 9850T Freeview stb. Sky digital picture is perfect which tells me the plasma is not at fault. Freeview is connected to TiVo by scart and from there to plasma using a Syncblaster to PC input. Sky uses loopthrough on Freeview stb and TiVo to the same input. DVD and VCR are fine. Can anyone suggest where I may have a problem?