Dell Webcam Manager is an application that allows you to use the webcam. In order to fix the error, you need to reinstall the webcam driver. Go to Dell Support page, identify your computer model, select your operating system and download the provided webcam driver. After that, go to Start > Control Panel > Hardware and Sound > Device Manager, locate your webcam device, right-click the driver and select Update Driver Software. Use the Browse option to navigate to the installation package, select the driver and install it following the self-explained steps.