Check that the contact between IR sensor and tuner is reliable. Often the IR sensor connectors sets against the wall of PC case and is not inserted completely.
Check that batteries are fresh and inserted properly to remote control. You may check that remote control works by looking to them through digital camera. They are sensitive to the IR light of remote control. You can see flashes from LED of remote control.
Also check that remote control is enabled in settings of Behold TV application.