Are those Verbatim DVD+DL discs 2.4x or 8x ones? I'm asking because the 4163B does not have firmware support for the 8x version, so it is possible that those will not work on it at all.
There is no point trying to browse a blank DVD disc using Windows explorer. All you will get is an error message!
Just in case it is the software you are using that is at fault, try burning one of those Verbatim DVD+DL discs with Imgburn (http://www.imgburn.com) and see if that works. Imgburn is freeware.
Also, what version of firmware is your 4163B using?