here's my two cents worth.
In the earlier (Version 2) of WMM I seem to remember that one was limited to 100 photos with transitions - I remember having to cull photos from the project to allow it to continue. I don't know if that has been resolved in the current (Version 6) of WMM that you are (apparently) using. That could be the cause of the crashes once you start to publish.
If WMM no longer has such limits I would guess that computer memory may be the problem. Video rendering is, as you know, very memory intensive.
I wonder if the following workaround might help you. Try creating several smaller projects in WMM and then bring them successively into the DVD Maker (using Add Files) so that ultimately you will have your original full project back.
It would not make sense for MS to have provided a DVD Maker facility if the DVD was limited to 100 photos with transitions.
One other question - did the 5 minutes movies you are including run in the preview (i.e. are they compatible with WMM)?
Hope others can pick up on this to resolve the problem for you. (I use ProShow Gold for creating slide show presentations like yours and I generally use Nero top burn my CDs and DVDs).