Toshiba sd-310vu dvd player makes

The motor that spins the disk rests on rubber shocks. The rear shocks wear out over time allowing the disk to set uneven and rub eventually stopping the disk and giving a disk error. To fix simply put one small flat washer under each of the rear shocks this will level the motor and stop it from rubbing. 

I have the same model DVD Player and am experiencing similar problems. I was having trouble with the DVD player locking up during a movie. So far I have cleaned the lens several times with 2 seperate dvd cleaners and even taken the player apart and cleaned the lens manually. After I cleaned the lens myself, I have noticed the lockups are fewer and sometimes the machine can fix itself from a lockup. This model DVD player has a badly positioned gear driving the lens, and a faulty lens alignment. Both can be fixed with a little know-how tho. (Still working on it... hope this information helps you out in some bit)