Cannot burn dvd on macbook pro

What software are u using, try titanium toaster or Burn X.

This may be caused by Burning software or hardware failure. Below are some possible reasons. Possibility 1.
There is something wrong with the super-drive. When your DVD drive is bad or damaged, the MacBook DVD drive is not reading.
Possibility 2.
There is some scratched in the DVD or the DVD gets dust.
Possibility 3.
Such kind of issues happens after you have upgraded OSX to Lion or Mountain Lion.
Possibility 4.
Sometimes, it hits a block when Mac DVD player to read a DVD encrypted with region code which is not matching region code of your DVD player. So your DVD player will go to a black screen and then unexpectedly quit.
Moreover, you can fix this issue by referring to below solutions. Solution 1.
You are able to lean the Super-Drive's slot with compressed gas/vacuum cleaner. If the problem "MacBook not reading DVD" still exists, you have to repair the DVD drive or purchase a new one in order to watch DVD movies on Mac.
Solution 2.
If your DVD is scratched or dirty, your DVD player can accept discs but will fail to read it. As we all know, the default DVD player is very sensitive to the quality of DVD disc, if your DVD is scratched or dirty, you can get help from a third party.
Solution 3.
Try to reset NVRAM (or PRAM). Shut down your MacBook Pro and turn it on later. When you hear the start-up sound, press and hold the Command-Option-P-R keys at once until the MacBook Pro restarts and you hear the start-up sound again
Solution 4.
It is suggested to rip DVD any video formats supported by Mac to solve "MacBook DVD drive not reading" problem.
For more details, check: Fixed: MacBook Pro Not Reading DVD

Some DVD disc work better than others. I have found that Verbaitim works best. The are a bit more costly than others, but the extra cost is well worth the fact that they work very well. Also, if for some reason a disc does not function as it should, do this wash the disc with warm soap and water, dry very carefully, then try using it again. This will work for discs that do not read as well as they should.