Yup, after a bit of reading, I now strongly suspect that metadata (ie, like the number of stars) is stored separately in Elements' database and not with the file. This is exactly the same way that Organizer's big brother, Lightroom does it.
So, if you simply copy the original file from your drive, it won't have any of the changes that you made in Organizer (eg, stars, keywords, etc.) "baked in" because this information is, at this point, only available in Organizers DB.
Instead, export the file(s) that you want from Organizer into a new file (or group of files), and that version should incorporate all the work you did on them. You then can take these new files into Adobe Revel, and the star rating should show up.
BTW, you don't have to do this on a file-by-file basis. You can do a "batch" export. Here's a couple of tutorials on exporting:
http://helpx.adobe.com/elements-organizer/using/export-photos-folder.html
http://www.lynda.com/Elements-tutorials/Exporting-photos-from-Organizer/117104/121067-4.html
Why don't you test my theory on the photo of the dog that you have already posted. Do the export (as described above), and post the results (ie, the new file) here. I'll then check to see if the star rating is now incorporated. Don't forget to save the exported file in a new location and with a slightly different name so that it can easily be distinguished from the original.
HTH,
Tom M
PS - Not having either Elements or Revel on my computer, I'm working at a real disadvantage. Another possibility (that, unfortunately, I can't test) is that if Adobe Elements Organizer provides a direct "Export to Revel" tool, my guess is that it should automatically incorporate the stars and keywords that you added, but something else is wrong. Again, hopefully, someone with a new version of Elements and an account at Revil will come along and check out this possibility.