Well, I tried with DVD-R, DVD-RW and DVD+R. Brands: Phillips, Sony, Verbatim, Maxprint, LG and 2 random generic, at speeds of 2x, 2.4x, 3x and 4x. Always got the same problem. NeoGamma doesn't play too. By the way, I didn't tried Gecko OS yet, I'll try it and post the results as soon as possible.