Peal Player? You mean Real Player perhaps?
I’d try it in VLC ( a free video player which operates independently of any installed codecs) http://www.videolan.org/vlc/
Also, rip it to the hard drive and see if it will play from there without issues. I know its not encrypted, but use a good ripping program like DVDDecrypter in file mode. (Decrypter only works on valid dvd video, so I’d like to see if it can recognize and rip it correctly). You can download DVDDecrypter from www.mrbass.org
You can also examine the files with MediaInfo to see the specifications of the video. If you post them here we can tell you if they are standard for dvd video, but I suspect they are, since they play on your dvd player.