of course they are susceptible to interference.
but
inteference might not be the problem.
it could be too many things connected to the television.
or
it could be a ground loop coming into the television from the new satellite box.
or
a ground loop in the television itself from two different things connected.
if the rca cables were working just fine before, maybe you should keep them and try a different HDMI cable.
if that doesnt work, ask for a new receiver.
if that doesnt work, try a power conditioner that specifically says something about isolating everything to their own grid.
if that doesnt work..
maybe the dvd player is the problem.
reality of the situation..
maybe the rca cables are junk.
but
it could be something else.
if you...