I also have the problem ! I agree that it is very annoying when discovering it outdoor!
Unfortunately, there is probably no solution to repair this problem without your computer.
I think that the bug may happen when the space left on the memory is not large enough to store the whole GPX file. In this case, the uploaded GPX file might be corrupted.
When i have this problem, i clean all the saved traces and waypoints and i upload again the GPX files
This way, it works fine. It seems that, after a clean, the memory is free and the data can be uploaded without being corrupted.
I missed to check the files last time it happened to me.
Could anyone check the file on the GPS to see if it is complete (simply open it with Wordpad) ?
