A few things that we noticed that might be helpful...
Once it is all set up, it will populate each race after you start the race. The initial Milesplit live result page will show no events before the 1st race starts, and that is completely fine. As each race starts in ART, the events and results will populate.
The "progress" prompt on Milesplit Live for each event will always show as "completed" even as the event is going on, and that is also fine. We tried to mess with it during one race in the Milesplit Live app and it just messed things up...
Finally, we usually hit the refresh button on "LIF File Export" when there is a break in the action, but the results do show up really quickly on Milesplit live.
Hope this helps!