Trouble importing from a DVD+R disc!!

I'd have to wonder about the disk.
You say you can't copy the files on to your computer?
Do you mean you can't see any files at all or that while you can see them you can't do anything with them?
The difference is important in telling us what could have gone wrong.

OK.
Put the DVD in the drive and right click on the drive in MY Computer.
Click on Open.
You should see a folder with all your music in it.
Open the folder and copy one song to your desk top (pick one you can find easily in your iTunes library).
Open iTunes, find the song as it's listed in the library and drag and drop the back up there.
Now double click on it and see if it plays.
If it does create a file on your desktop and copy all the music from the DVD into it.
Now go into My Music>iTunes>iTunes Music and drag and drop the whole folder into that last folder ( double check where it's going by opening the folder and checking to be sure.).
Alternatively you have the option of using the Add Folder to Library from the drop down menu but that doesn't seem to have worked for you.

DVD+R will not work. You must use DVD-R. I had this same issue.