I thought this other low memory issue might be of interest to some. This is a copy and paste of the message I sent to e-on's tech support. To me this shows the memory leak or whatever it is has a wider scope than just imports.  (For those who didn't read my former posts, I have 4 gigs of memory  on a system way beyond Vista requirements.)  Also the purge and history flush commands don't always work.

When I opened the file to render it had resources of 89%. The file was strictly Vue except for 5 alpha planes of trees. There were 12 objects and 1 light. The atmosphere was spectral. There were 5,305 polygons. I rendered at Ultra with Multipass enabled. I used 2400 x 1800 at 300 dpi.

I rendered this during the night. I saw it took a little over 6 hours. In the morning, I fortunately was able to save the images because immediately after, I got a low memory warning. The memory was at 22%.

I tried to both purge and flush the history and it did not make a difference. Those two commands obviously did not work.

I have been writing articles for Renderosity on Vista for the past few weeks and I tested extensively Vue 6 Infinite pre release not using the last update (I used the update before the last). I never had a problem. I did renders for over 24 hours. I did not check memory because there never seemed to be a need for it so it is hard to compare.