Ok well, the icon of the bars and the question mark is Myriad waiting for level to rise above the threshold that you set in the Audiowall Global Settings.
It sounds like Myriad is talking to the sound device OK, but it is not getting anything loud enough or any audio at all.
At this stage, I would check your soundcard, the driver, the physical wiring.
If you still have problems it's best to elevate the enquiry to our official support team.
Broadcast Radio Ltd