OpenPLi working ok on 27.5w but..................

I have OpenPLi working ok on 27.5w but i have a small problem which i am sure i didn't have before if i am recording a program and i watch something on the hard drive i recorded earlier it screws the recording  i am doing up!! the recording is still there but it will say it is 60mins but if you try to play it just gives a black screen and nothing is actually there I am sure before i did not have this problem and i could watch something and record at the same time.. can anyone shed any light on this problem please?? thanks guys