The usual problems we see with dedicated file-hosting or "dropbox" services is that they require the user to go through a download page for that service in order to download the file and cannot provide a static, direct URL to the actual file itself, and/or they require the file to be downloaded with an actual Web browser program, rather than a server-side utility like our download scripts would use to access the remote file.
If you're not sure whether any of the above apply to you, feel free to send your box.net file URL to our Support team, and we'd be glad to test that ourselves for you:
https://www.e-junkie.com/ej/contact.php
