Hi,
This means that the file that you have in your CSV already exists in the folder media/com_hikashop/upload folder but with a different size than the file of your URL.
So it means that it's a different file than the one that you already have and since they all go into the same folder, the system has to change its name or product which was already there with a file with the same name would get the new file instead of keeping the old one.
On top of that, 0 means that the file was just created but without any content. So you should actually delete these before the import and it should work normally.