The "no title" just means it doesn't see it as a dvd disk.
I'd do a small test project to see what is actually working.
Export a 5 minute sequence from Premiere (not dynamic link) using the MPEG2-DVD preset. That will create an m2v and a wav (or a3c, if you select dolby at that step - I usually leave it for Encore).
In Encore, create a new project. Add one menu. Delete all but one of the buttons.
Import "as timeline" the m2v/wav (select both). In the Project Panel, look at the "DVD Transcode Status" column. Does it say "Don't Transcode"?
In the build panel, select DVD and DVD Image. Use Toast to burn. Does that work? If not, it is something more than your big project.
The iso may be small enough for you to upload and for us to test.