Download
CloneCD from
www.slysoft.com and give that a try as you get 21 days free trial (I take it it the disc size is less than 4.7 gig?) As it is not an original DVD, there is not really anything effective he could have done to protect it. It could be that it is just a crap copy and has errors on the disc.
Another good tool to use for this would be DVDDecrypter, using ISO read mode.
Let me know how you get on.