Thank you for your post.
It's not clear if these files used to display, but not longer display in the Open Remote dialog box.
Close one of the problem files in FileMaker Server, and open it with FileMaker Pro. Pull down the File menu and select "Sharing -> FileMaker Network...". In the next dialog box, select the file and make sure network access is not set to "No users". In addition, below that, make sure the option "Don't display in Open Remote File dialog" is unchecked. Otherwise, this will not show under Open Remote. Once done, click OK, close the file, move it back to FileMaker Server and open it. Then, try to access it remotely through Open Remote.
Please keep me updated.
Thank you so much for that rapid response!! That was the problem and it would have been a long time before I would have remembered I had to do that.