[pedigree]

It doesnt overwrite any files at all, none, nada, zero. If prompted for an overwrite, it might be because it puts files into subfolders. You upload the contents of the upload folder (but not the upload folder itself) to the root folder of your forum (the one that contains register.php) and all the folders as well, this places the correct files into the correct folders. You then import the product_vbstopforumspam*.xml file in your pluigin manager.

Its exactly what Samir said but if you dont have FTP upload access and your provider goes you some crappy webinterface, then youll need to upload files mnaully into the correct folders