I have had a similar thing happen, I was using one of the boris products and it just could not get past the place in the file. Re did at a lower bit rate and it worked wondefully.
I got a very similar error, with this not-helpful message:
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Warning: An error occurred while writing a file.
The reason for the error could not be determined.
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This happened on my last TWO projects (over an hour long each, but the MPEG plus AC3 files don't come even close to exceeding 4+ gigabytes).
I completely re-rendered the first -project in Vegas, TWICE, and it finally worked OK in DVDA. My second project is now stalled-out, unable to continue.