Well I would understand why it would not display, its not even uploaded to the server! http://www.summitpost.org/download.php?f=716327.
I've tested earlier on that certain gpx files don't upload to sp. What I use is a online converter to get the exact sp format
So here is a idea, upload the file to this site: http://www.gpsies.com/upload.do?uploadMode=convert
Convert it to GPX Track
Then show options at the bottom
Click the "Add / replace elevation" check box.
Then hit convert. Reupload it to the page and see if it works.
Edit: Confirmed my test. When I convert the gpx file to a "GPX Route" (different from GPX Track) format it does not work.
The gpx file that does not work is virtually the same as the one in the trip report I mentioned a few posts ago that does work. So either people need to convert them, or SP needs to be able to read the format.
How can you tell the format? Open the gpx file in txt mode (a simple text editor to see the code structure) which there is a key difference. Notice before each coordinate something that says (depends on what code version you have)
<rtept lat="48.50992076" lon="-121.226298">
for each coordinate. This is the code version that does not work for sp while the version that I know works
<trkpt lat="48.50982711" lon="-121.225123">
Works just fine. I made it so the important part of the difference was bold text.
This is just a guess, so it's not that sp's map system cannot read the gpx file, it does not properly upload to the site.