I see someone else has submitted this under platform/OS X as well.
This occurred with a 65-frame pano which I was attempting to render with transmercator projection. Rendering works fine with equirectangular projection.
Tried this on 2 different XP 32-bit machines with the same result, both using the official 0.7.0 release.
Log as follows:
C:\Program\ Files\Hugin\bin\nona -z...
2009-05-30 19:54:03 UTC in Hugin