Looks like you are trying to make a Video DVD with two 700MB compressed AVIs.
Try changing your disc size to something large enough to fit, and then 'burn to an .ISO'. This will make an image which is too big to fit on a single-layer DVD.
Use Roxio Disc Copier to burn that ISO to a 4.7GB disc. It will recode it to fit.
Have a thorough read of this topic, too, please.
http://forums.support.roxio.com/index.php?showtopic=36114Regards,
Brendon