Drives not recognized with ultra 7 update

I have tried to download and install Nero7 update …7.5.9.0A
Release Date: November 27th, 2006 three times. After each installation I received the message… drives (DVD) not recognized. In each case I used system restore and the drives returned. I started with Nero 6 ultra years ago. This is the first problem I’ve ever had with an update .