I see.

I used tkregister2 to fix the talairach.xfm output and loaded the fixed registration in Freeview. In the screenshot I have attached, my cursor is near the anterior commissure. Freeview shows that the RAS coordinate at this point is ~0,0,0, as expected. Is this RAS a Talairach RAS or something else? Are the coordinates corresponding to millimeters?

It does look like there is a constant offset from the displayed RAS and the displayed Tkr RAS. 

Thanks!

Victor