It can't hurt to update Nero 6 to 18.104.22.168 as chef suggested (but NOT to Nero 7 - buggy and requires a separate license besides). It is possible some older versions of Nero 6 won't work correctly with the drive and that may improve with the update to 22.214.171.124.
I'm not sure about CloneDVD but viewing the contents of a blank DVD with Windows explorer is totally pointless - explorer is incapable of browsing blank discs and will always give you some kind of error. You cannot check if a disc is blank that way. It is not the same as checking if a floppy disc is blank.
Other than that, if you can check in Device Manager if your 4163B is detected correctly under Win98 (and that there are no device conflicts with it), I cannot think of anything much else to try. I have never used any DVD writer under Win98 so I don't know how well they work under it, or even if they will work under it.