Having trouble with NERO startsmart

Ok i just downloaded and installed NERO startsmart as i have a couple of films i want to burn onto dvd.

The problem is im trying to burn 6 episodes of ben 10 which are 20mins long roughly 178mb each and im trying to burn them on a standard dvd-r or a dvd-rw but whenever i move the files over nero says that im over the time frame of the dvd which isnt true as im trying to put just over 1gb of film on a dvd that takes 4.7gb.

can anyone help me please thanks