I've run into memory issues a few times. Only thing I can suggest is saving the scene for batch render and  using smaller tiles. Then run the batch and if memory usage goes too high (paging memory goes past what's available and starts hitting virtual memory), pause it and then restart after the memory use settles down. (If you're using nodes, perhaps they need more memory too?)

I'm not sure if that's your problem or not. But it helped for my renders, might be worth a shot.

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Barbequed Pixels?

Your friendly neighborhood Wings3D nut.
Also feel free to browse my freebies at ShareCG.
There might be something worth downloading.