Error recording with Philips sdvd8441

Hey friends,

I`m facing some problems with my DVD recoding drive philips sdvd8441.
When I burn DVD´s (-R or +R), the process goes on normally.
But after it finishes, the media content is empty.
In the botton of the media, I can see the mark of the area recorded.
When I use - ou + RW discs, the content of the media can be viewed with no problems.

If someone could help me, I ould be very grateful.