Error code 34

Everything in my game keeps on deleting itself. My seven generations save files? Gone. I got over that though, what I'm not over is that not matter how many times I try to make a new legacy it just won't work. I'm considering it is my disc, I've had this disc for so long, but I don't know. Every time I save it gives me the Error Code 34 and I tried looking it up but I didn't get much results about it.