Try burning at 4x, and if that doesn't work, try with high quality blanks, such as Verbatim and Taiyo Yuden.
I have tried burning at 2,4x and the same problem occured.
Before I burned like 10DVDs from this spindl.
Benq is quite well-known label, isn't it?
And it doesn't work because ImgBurn, DVDs or DVD burner?