Well I am pretty sure that you have a3 installed, but I am also pretty sure that the A3 launcher will allow you to assign a path to the a3 client. I am at work right now so I cannot open the a3l to tell you exactly what to click on but I'd start with assigning it a path to your local client, also have you tried redownloading a3? also if you have more than one hard drive, try just putting it on C drive instead.
Do this, delete the battleye folder, the arma 3 exe files in your a3 game folder, then verify the game forcing it to replace those file. This is really a bat in the dark here without any logs or anything like that.
Are you using a different computer? Your Koth profile is stored on your computer, not on the Koth server.