This had me stumped for a while.
When submitting an app, if you provide a URL to a manifest encoded in
UTF-8 with a BOM, it always returns "JSON parse error". If you remove
the BOM, it accepts it. Think you might want to fix that - on Windows
the BOM is pretty much a standard way of encoding UTF-8 text files.
Thanks,
Ashley Gullen
Scirra.com