Not enough free disk space

Trying to burn a dvd using my optical drive (which i know its good since its brand new) and using Toast 11 Titanium. I keep running into the issue of the whole thing encoding, but right before writing the disk it will stop and say "Not enough free disk space. 4gb needed, 1.97gb available. continue?". i tried to save it as a disk image but it wont let me do that either. Not sure how to fix this! and when im burning a dvd since it isnt a video-ts file it doesnt have the box for compress-to-fit-dvd or whatever its called. Help???