Problem adding files to a previously burnt DVD

[qanda]This thread is about the Lite-On SHW-160P6S. Click here to see full specs[/qanda]I have tried adding files to a previously burnt DVD, after the re-burn was completed the files where not available inside of Windows XP to view or re-burn.
If the file or files where added to a sub directory all files and child sub directories are now gone. In most cases the DVD is now closed even through
I had asked for it to remain open.
This only happens with DVD disks, CD-R disks work just fine!
Does anyone have a answer to this frustrating problem. I have enough coasters for the next while. :sad:

I have two different burners and have tested both and both are unable to reburn a DVD without losing the previously burnt data. I am using Windows XP and have a Intel E8400 2-GB or Memory.

Thanks to all!

What program did you use to burn the dvd. What type of dvd was it? Was it DVD-RW?