Hi. I thought I would post this in case anyone else was having the same problem.
I was having the hardest time getting the correct driver installed so that I could use STDFU Tester v3.0.1 correctly and flash my N+2 to 4.3 firmware. Either I already had, or the installer was installing a 2009 version of STTub30.sys in my WindowsSystem32drivers directory. I was unable to flash the firmware according to the instructions in the forum. On my third attempt on a third computer, a 2012 version of STTub30.sys appeared in the directory (don't know how, all three laptops are Windows 7, and I thought all were set up the same, I guess not). Anyway, To fix my problems on the other two machines, I installed STDFU Tester v3.0.1, then copied and replaced the attached 2012 version of the file over the 2009 version, and tada, the software all worked and I was able to flash the firmware. I hope this can help someone.