Yes its a problem that needs fixing. Depends on where you live , cost of repair would be around 400. You are better off geting a same size TV now with better picture quality and features now a days.
I have had the same line at the bottom on my tv Samsung 2012 Model Full HD 3D 6 series. ( forgot the model number) . First the right side a 10x10 section started flickering and then it mended it self after a few days. Whats left was this line at the bottom which was visible all the time. Mine was located 1 inch above the edge on the right side and faded away in the middle of the screen.