[EDIT]Ah, wait... I see the issue. According to the log, it looks like you guys changed the 64-bit TrackIR .dll to scptrackir64.dll instead of simply scptrackir.dll. I've been using the original 64-bit-compiled scptrackir.dll and didn't realize there was a change.
[EDIT 2] Yup, there it is. Works now.