Low sound and hissing coming through

Just bought a new DK Digital339 player - plays everything under then, however - I can hear the sound from the tv channel below bleeding through when I play a dvd. I have to turn the sound up a little when I want to watch a dvd - which is normally the case but in doing so I can hear the tv playing underneath what ever I am watching, if I turn the channel to a blank one then switch back to the Av the dvd is on I can hear hissing. Is this a problem with the player or with the Scart leads I have connectedit with?

I have a Panasonic PD50 32" and have got it going into RGB Scart input on the TV. I was wondering which connection is best from SCART or S-Video aswell?