Thank You both. I'll start looking for external burner. I've set the max burning speed in ImgBurn to 6x for now, I will lower it again, and again until those verify errors stop showing. I forgot to mention that even with the 8x speed, they show up roughly every 10th DVD. But I'll burn at lover speeds.
As for that read option that You recommend volvofl10, I don't think it would have any effect, since mu drive's max read speed for DVD+-R is already 8x. Don't have a standalone dvd player, but every time the verify fails, I try to copy that disc on a HD, just to be sure, and it always failed. But, if it's a video file, you can forward over the damaged place, so DVD isn't wasted completely. Thank You for your time.