Hi archigrafix,
You may be reaching the maximum amount of system memory available to a process on a 32bit OS.
Check the task manager during the obj parsing and voxelization. The memory usage for octane.exe should be listed.
As an example when I load a 3mil poly (6mil tris) obj file on the 64bit version the memory usage will peak to about 5GB during parsing and voxelization.
This same file causes the 32bit version to crash due to process memory limits. As far as i know the limit for a 32bit process on a 32bit OS is 2GB (although in some setups i believe 3GB is also possible) so keep an eye on the memory usage, if it is reaching high numbers and then octane crashes like this:
Then i am pretty sure this is your problem. The only solution is to upgrade to a 64bit OS or limit the poly size of the mesh.
(Just out of interest once loaded in the 64bit version my 6mil tris scene only uses about 900MB of VRAM. So in your case, your scene may be easily able to fit into your VRAM but the system memory required during parsing and voxelization is actually the problem).
Let me know how it goes...
Cheers
Chris.