please help me !!!!

[wordave]

i have been using alcohol 120% and i have 2 dvd writers in pc when i go through the stages of setting up to back up my dvds i see there is an option to use multiple dvd recorders i would like to use this but it is faded out grey and i carnt sellect it dont know why tried looking at settings and find this is no good has anyone have any ideas on this problem or how to solve it thank you ps i can do this with nero 6 but not with this software