You can download the DVD-RAM driver at the LGE US site. At the moment you'll find it in Drivers -> CD-RW. Just check the file is the right one because they are currently mislabeled and there is a new DVD-writer section, so I suppose it will end up there in due course.
The other way is to install InCD (may be just the reader but I haven't tried).
Both ways have worked fine with my GSA-4082B, although I'm not convinced about how InCD formats DVD-RAM.
 should have added that I'm using w2k, not w98 - but w2k only supports UDF v1.5 so the drivers are needed for that too - so I presume w98 will work fine [/edit]