I also have a Nforce4 Chipset (MSI Board). The first time I flashed my drive I used SATA-Port 1, but the second time Port1 and Port2 didnt worked.
I used Port 3 it worked very well for me, I dont know why Port1/2 didnt work ...
I uploaded for you the version which I used, maybe it will help you.
Try it with Port 1,2 and 3. Good Luck!http://rapidshare.com/files/34477037/MTKFLASH-NFORCE4.rar.html