Problem scenario: When trying to use PowerShell to download a file, get you this error 'Error calling "DownloadFile" with "2" argument(s): "An Exception occurred during a WebClient request."'
Solution: Make sure you have ample space on the disk and make sure the destination folder exists. A typo in the path or if the folder not existing could cause this error. Insufficient disk space could also cause the problem. Is the file you are trying to download very big?