DMA setting is usually the culprit in slow burns with an IDE interface drive. But you've checked to see Current Transfer Mode is in Ultra DMA 2.
What program is he using? Does he have to convert the film to dvd-video format, or is this just for burning?
My advice is to test the drive using a different source...just a data burn, and use ImgBurn for this process. ImgBurn is a free program, highly recommended and found here: www.imgburn.com
Use good quality media (Verbatim 16x) and don't use the highest burn speed available in ImgBurn. Try one at 4x or 6x (if 6x is one of the listed speeds in ImgBurn). Once the burn is completed, post the log file here. You can find it by clicking Help-->ImgBurn Logs.
Does he have the latest firmware for the drive? It can be found here: http://www.liteonit.com/global/index.php?option=com_content&task=view&id=174&Itemid=88&limit=1&limitstart=2