Error message.. Fix the default altitude. But HOW

HI

Just been getting to grips with the Mission Planner. It was working fine and I had made and saved a couple of possible missions for the future but…I obviously made a mistake and now when trying to plan a new mission it just tells me to FIX THE DEFAULT ALTITUDE. I am totally baffled… There is nothing I can find that will even help me. I even uninstalled the whole thing and re downloaded it but the same thing happens.
I can go to the saved missions and try to upload one, It does but without the track and waypoints though the waypoint info is there below the main screen.
So can someone please tell me how to fix this ERROR MESSAGE before I go right off the whole thing.

Totally frustrated.
Please help

Elderlygent.

[color=#004000]Moved to GCS/Mission Planner
Please post your support requests to the appropriate subforum![/color]

Ha!!! sorted it out now.