I seem to get most errors from trying to write dvds to fast....dont write at the maximum speed you can its better to slow down the writing a bit.
I will take slightly longer but it will be worth the time not to waste money.
I use click here to get dvd discs which are cheap.
Plus for the first few use DVD-RW discs as you can rewite on these if they go wrong so you dont waste discs.
Hope this helps