Your bug report

#20781: Xemacs 21.4.22 MaC OS Yosmite: (customize-option 'TeX-view-program-list) fails with error

which was filed against the auctex package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 20781@debbugs.gnu.org.

-- 
20781: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20781
GNU Bug Tracking System
Contact help-debbugs@gnu.org with problems