Error setting DVD Repository

[bharmonoxs]

I do this step :

1. System --> Administration --> Synaptic Package Manager
2. Type Password User
3. Chose Settings --> Repositories
4. Chose Tab Third-Party Software
5. input DVD Repositories
6. Click Add CD Rom
7. Waiting and click Close
8. Click Reload bottom
9. Repeated another Repo

But in point 6, after click Add CD-Room, the statment is: "Please insert a disk in the drive:",
And then input DVD Repository disc 1
at proses scanning, the response is:

"E: Failed to mount the cdrom.", dvdrom like unknown, but DVD can easy to browse.
Anybody can help me?

[zvacet]

Read this (http://ubuntuforums.org/showthread.php?t=352460) (step 7)

[bharmonoxs]

Thank's for your answer, but the problem is DVD can't reading the Repository DVD when insert in DVD Rom. But DVD easy to read in another windows. My DVD room detect in /dev/sr0