The package is way behind upstream, so please update
*** This bug has been marked as a duplicate of 118100 ***
This is a different issue and has nothing todo with bug #118100, because XEmacs and GNU Emacs packaging for AUCTeX are independent from each other. The more the package that this ebuild tries to download is not available anymore on the XEmacs FTP.
Bleh, sorry. Anyway, don't hold your breath, we don't have any xemacs devs right now. :/
An updated ebuild for xemacs package 1.46 (which seems to resemble auctex version 11.55, and it the latest stable xemacs package) is available in my xemacs overlay: http://moving-innovations.com/svn/xemacs/
app-xemacs/auctex-1.46 is now in portage.