Problem with Disk Drive?

So I have a macbook pro 5,3

Today I tried to burn a dmg image to a DVD+R DL. I have seen in system profiler that I support DL. So I started the burn in disk utility. Here is what happened:

Preparing data to burn: 20 minutes
Finishing burn: still going.
System profile: now says i don't support DL even though it did say it 10 minutes ago.

Any ideas what's going on here?

Sounds like your optical drive may have gone south. Try shutting down and restarting to see if the DL capability gets picked up again. Also, DL burning is a bit hit and miss. Try another brand of DL media if possible.

Regards.