I struggled a great deal of time with the same problem, the problem is
with the new hosted mode, it uses a war folder (defaults to
{projectRoot}/war ) and it expects the host html file to sit there.
Put the logLevel to DEBUG or SPAM to get more details about the hosted
mode inner workings.
Hope it helps, and if it doesn't, report back with your project
structure and the arguments you're passing to the hosted mode.
Cheers,
Salvador