You write you want to download. Downloading in OutSystems means something that is on the OutSystems server or a file server that OutSystems has access too. Then the download will give you the binary that can be stored locally on your computer drive.
In your screenshot, you try to read a file from your local c: drive. Unless OutSystems runs on your computer too (which it doesn't) there is no way OutSystems will be able to connect to your computer to access that file.
It also makes me think you don't want to download, but you want to upload, from your local drive to outSystems. In that case you can use the Upload widget