First of all, make sure that your speakers or sound device is plugged in correctly before starting WATCHOUT.
If you have not setup you computer to be used with administator rights the WATCHOUT audio renderer might not have been installed correctly. If so, no matter of how many interfaces and drivers you install, you wont be able to select any audio output from your device.
This can become apparent if you have updated WATCHOUT remotely.
What you should do in this case is to update your WATCHOUT installation manually on the display computer, with administrator rights.