Lion not reading DVD

[Kuba77]

I've just noticed that Lion doesn't read some of my DVDs (previously written in Nero). I mean, name of DVD appears in Finder but it is greyed out and there's nothing I can do with it.
I'm sure Snow Leopard could read these DVDs without any issues.

Anyone got similar problem?

 

[harrisondavies]

Not a similar problem and don't wish to hijack, but quicktime also appears to have problems playing video files. randomly going out of sync and disrupting the picture, the only way to fix it is to click on the timeline to get it back in sync or reopen the file and scroll to where u left off.