Check the TV out settings from your video card - make sure it`s set to a 50Hz PAL mode (e.g. PAL-I, PAL-B, PAL-G).
If you still have issues, it may be a Macrovision-related problem (I`m not certain of this, though). You could always have a search around the net, and see if there`s a `Macrovision off` hack for whatever software you use.
Mike