The only thing I found out , is that I first have to start Arma and then press Alt+ tab which brings me back to desktop, start freetrack, go back to Arma and I can look around using freetrack.
But what is or caused your error I don't know.
If you suspect something is wrong with directx, just go to the site of microsoft and download the version for your OS.
Spoilerhttps://support.microsoft.com/en-us/kb/179113