I have the same drive, and same firmware, I have had mine for about a month, build date is feb 04. I use TDK 48x media (Ritek) and it seems fine, using nero 22.214.171.124 for the burning.
It does do one strange thing though after I do a burn and go to do another it drops the burn speed down one level, doesn't seem to matter what speed I pick for the 1st burn the 2nd burn nero always selects the speed 1 below what i used the time before, as I said before it works fine though. I do most of my burns at 24x unless it is music then it is 12x, I have tested burning data at most speeds up to and including 52x and had no problems so far.
I just remembered it does get a little picky with cd-rw discs I have a couple that I use for testing all the time and this drive has decided that it won't burn to 1 of them but my LDW-411S burns to it without a problem?