I don't think that's the problem. TinyWall's main service runs in the background and it doesn't use the credentials of the currently logged in user. When TinyWall asks for UAC permissions it is usually a sign that the service is not running and TinyWall is trying to repair itself (e.g. make autostart entries, start the service and others it depends on etc.) I can only guess, but I would look around and see that none of the service TinyWall needs are disabled, maybe check compatibilty with HIPS software installed on your computer.