copied dvd's fail after about one hour of viewing

I am using a liteon 411s burner with dvd shrink 3.2 and use nero to burn, most of my copies play well for in excess of one hour then slow up and stop, very annoying , am i doing something wrong and how do i fix this problem, any assistance would be most welcome

 

What brand of media(blank DVDs) are you using? What speed are you burning at?

 

hello , mainly use either laser or ritek and burn at four times speed. Sometimes the burn is successful all the way through. any help is greatly appreciated thanks

 

What format(-,+) do you use? Try burning at 2x for -R or 2.4x for +R. You may also want to see if there is a new firmware update for your burner.

 

thanks, Wolfnigger,have just d/loaded new firmware ,so will see if that makes a difference also will try burning at 2x speed , thanks for your suggestions , will let you know how we get on regards

 

thanks for the replys.problem solved by replacing burner with a new model, old burner was faulty.
best wishes to all great site cheers