Suggest performing minor Hard Disk maintenance by running your Disk Defragmenter (Start/Programs/Accessories/System Tools/Disk Defragmenter).
Also suggest checking for any SpyWare that might be inadvertently installed on your computer by using a program similar to Spybot Search & Destroy(http://www.spybot.info/en/index.html). You might be surprised to find what SpyWare has been installed on your computer.
I believe your problem is related to DVD media. Just because you have been using your current media on previous burns and didnâ€™t have problems doesnâ€™t mean your current problem is not DVD media related. DVD media manufactures experience quality control problems. There is no guarantee that each and every piece of DVD media is manufactured exactly the same.
To find out about the quality of the DVD media you are using suggest visiting the VideoHelp DVD Media List located at (http://www.videohelp.com/dvdmedia). There is a lot of cheap substandard DVD media being marketed these days.
Could you please provide some amplifying information. Please provide your DVD media, DVD Burner and DVD Burner Firmware.