Export a short gpx file from BaseCamp and look at that. Then, make sure your file is organized the same way. BaseCamp is picky about the order of some fields (when it shouldn't be). It also should report more information about what it doesn't like. The line that it failed on would be useful to know too.
There are several problems. One is some garbage at the very beginning. Another is the presence of characters that aren't allowed. The third is the presence of 3D after the equal signs.
Normally I would repair the file with Notepad, but this is a rather large file and Notepad might choke on it. To see the problems you can open the file with Notepad. The characters that aren't allowed will appear as a box and the same character preceded by an =.
Make a copy of your file and open it with Wordpad (not Word). This will automatically clean up the box characters, but will leave some unwanted equal signs. Now do the following:
1. Delete all the characters in the first line before/left of <?xml
2. Use the replace command to replace " =" with "" and replace all. Don't enter the ". On the Find line press the spacebar followed by = and leave the Replace with line blank. This will take a little time as the file is large.
3. Use the replace command to replace "=3D" with "=". Again, don't type in the " and there are no spaces.
Save the file and it should work. If it doesn't, there may be some stray "=" on the right side of some lines in the beginning of the file above <metadata>. Try removing those.
That file is messed up big time. There are invalid characters at the beginning and spread throughout the file. That makes it pretty hard to fix. Following BTLAAKE's pointers should get you there.
Fixed it with Notepad ++. File was sent by someone planning a motorcycle ride. I'm trying to figure out how he screwed up. At least now I have the routes. Used online XML validator tool and got rid of errors so BaseCamp could read it.
