Burning dvd in disk utility takes an aternity

Hi guys, I've been having some problems with the disk utility dvd burner. I was burning a copy of a program (about 5 gb) on a DVD Dual Layer, but it's been like 2 hours and it's still in the "finishing burn" phase. Also it's very silent, like the dvd is not being burned at all?

What should I do? Why does it take an eternity to burn dvds?
I have a MacBook Pro 15 inch, 10.5.8

Thanks for the help!

Edit: I misspelled "eternity" in the title

I tried burning it on Toast titanuim and got this message, Sense Key = Medium Error sense Code = 0x73, 0x03

What should I do?
please help