If you're saying that you don't see any disc menu templates, make sure you've installed all of the content for the program.
If you bought the boxed set, this content is on discs 4 and 5.
If you downloaded the program, you can download this content from the Adobe web site.
Steve - thanks for the response, but no, I mean that the rather elaborately constructed disc menus which were part of the E3 project were not read in to E10. The project now has no disc menus. I could construct new ones based on the E10 templates but I don't want to redo all that work.
It would seem to me that the disc menus are an important part of a project and I'm wondering why they seem to have been lost.
I am trying out the E10 trial version so have not installed all the optional E10 templates (yet); however if E10 needed them to open my E3 project it didn't say so. And E10 has "updated" my E3 project in-place so it is no longer openable in E3; fortunately I have a copy saved elsewhere.
I always highly recommend against starting a project in one version of the program and then finishing it in another. It nearly always leads to problems.
But between version 3 and version 10, I'm surprised the project even opens in version 10. The program has had some pretty major overhauls since 2006. Even worse, it likely corrupted the project so that you won't be able to successfully work with it in either version.
Hopefully version 3 made an auto-save of the project you can recover. But in any event, I highly recommend you always finish your project in the same version of the program you begin it.