The corner radius invalid thing happens when 3 consecutive waypoints don't meet certain criteria for distance and angles. It usually happens on flights after the first flight that have an abadonment point near another waypoint. This can easily be worked around by selecting the nearest corner waypoint while the blue verification line is showing so you start there instead of having that extra point in there that is causing the issues.
There will be a fix for this soon since we have been hearing about it a lot lately.
The maximum flight radius is something in the Map Pilot Pro settings that allows you to define an around outside of which you are not allowed to operate. It is under the 'User Interface' section in the settings labeled 'Enable Radius Guide'. When it is enabled you can define a maximum radius for your operating area.
Or, you didn't have a solid GPS fix yet and it was thinking you were somewhere else. You cannot upload a flight into the system that is further away than the aircraft can physically fly to in a single battery. So just check the location of the red triangle with respect to the defined flight path.
