When trying to roll back to beta 4 TrackIR in game is still porked. Here is a tempory fix untill they get beta 5 working.
This, to me at least, is because uninstalling the program dosen't delete all the files. You have probably noticed a garbled message appear when you have tried to uninstall the program, you probably clicked "ignore" button.
The solution is to go back to the beta 4 software, but first, in order to totally get rid of the TrackIR files, download Revo uninstaller. (it's free, and it should be top of a google search)
When Revo is installed, open it and simply click on TrackIR press the uninstall button and follow the instuctions.
N.B FIRST MAKE A COPY OF YOUR PROFILES (I COPIED MINE TO MY DESKTOP) MAKE SURE YOU OPT FOR THE MOST AGGRESIVE CLEAN OUT (ADVANCED).
Then restart and re-install TrackIR beta 4.