Have you tried to not let CSVI create the thumbnails and let VirtueMart do so?
yes, CSVI makes thumbnails in resized folder on the server without any size at the end.
Virtuarmart is doing it with size at the end.
That solves the problem then or not?
The import log looks fine except that the thumbnails have the wrong name. I checked the changelog and this is an issue fixed in CSVI 2.
You could modify VirtueMart to just take a normal image name and not attach the size to it or let VirtueMart create the thumb image.