I just installed 2.10 and had the same problem. No WYSIWYG editor in a WYSIWYG section.
I found the cause was a coding issue in /modules/ckeditor/include.php where line 58 had:
$ModPath = str_replace($url['path'],'',$modRelPath).'/';
This removes all slashes from the path, wherever they might be, then tacks one on the end.
The problem was that if $modRelPath had slashes within it, they were also removed, breaking the path.
So I commented out that line and put in:
$ModPath = $modRelPath.'/';
Even if it added an unnecessary slash at the end (because $modRelPath already had one possibly) *nix doesn't care about repeating slashes, just treat them as a single slash.
Now the editor shows just fine.