I'm trying out the demo version of TF and have successfully drawn tracks and generated elevation profiles for several legs of an upcoming backpack trip. Today I drew a track for a different hike (using the map drawing tool). However, when I profile the track I get a flat profile, indicating there is no elevation data for the track I mapped. I tried adding elevation data via the Climbing Analysis dialogue, but I get an error message saying "some elevation data is missing from TF's local cache". How can I add elevation data to my track, and why wasn't elevation data generated when I originally drew the track?