File Browser problem

[LoneAngelIbesu]

You need to upload files through the File Browser. The files on your server aren't stored on your computer, but on an actual web server.

[Rufus]

Drag your files from your computer into the levels folder on the server you're trying to upload levels for. Alternatively, you can right click in the levels folder on the File Browser and click "Upload file(s)" but dragging is easier in my opinion.