Copying Nothing

[hensucker]

Well everyone this may seem strange, now i have been away 5 weeks working out of town, before i left everything was fine my pc wasnt used at all while away by anyone.
now i am home i have been copying a few dvds for the christmas rush, now then if i copy a dvd to dvd it is fine, but when copying video files to dvd something strange happens.
i have used dvdsanta and convertxtodvd both with the same results, here is what happens, the programs go through the whole encoding process, then they set in to burn, it then goes through the whole burning process and says operation complete at the end, the disc then gets spat out and loking at the reverse of the disc there are no marks scratches or nothing and there is a visible data line where it has burnt.
but i tried to play it in both of my pcs and 1 of my household dvd players and nothing is detected, my computer shows nothing and says disc is empty and so does nero info tool.
Is there any explanation for this?
my firmware is upto date, my codecs i believe should be upto date, the region on my drive is set correctly.
Thanks.

[hensucker]

Just recently in addition to this, i have used nero vision to copy one of the files in question and it as worked, so now it hasnt become a major problem but more of a mystery, i prefered the other programs because i seem to ge better results than that of nero vision.

[Krispy Kritter]

My first thought would be a bad burner. But, since Nero vision is working properly, that seems to rule out the burner. So I expect the issue lies within the other app(s). I would uninstall and reinstall convertxtodvd.