Is it a perticularly large project?
I had something that looked a little like that (admittedly at earlier steps in the project) when running out of RAM. My scenario was complicated by an unrelated hardware fualt though -- one of those complicated and unsatisfying "several things happening at once, then it all went a awy when I started troubleshooting" situations.
I doubt that's the answer, but it's worth considering.
thanks,
JRP