Saving custom options in 2.5.12

I'm getting the following error when trying to click Options->Save Options to Init File: Signaling: (wrong-type-argument number-char-or-marker-p nil) pp-to-string((quote blink-paren)) pp((quote blink-paren)) custom-save-variable-internal(paren-mode) mapc-internal(custom-save-variable-internal (paren-mode)) mapc(custom-save-variable-internal (paren-mode)) custom-save-variables() custom-save-all() #<compiled-function nil "...(7)" [mapatoms #<compiled-function ... "...(93)" ... 7> custom-save-all] 2 ("/luser/lib/xemacs-21.5-b12/lisp/cus-edit.elc" . 86509) nil>() call-interactively(customize-save-customized) (dispatch-event "[internal]") Compiled under RedHat 7.3 [Lucid] (i686-pc-linux). -- Clay Haapala (chaapala(a)cisco.com) Cisco Systems, Inc. SRBU PGP: C89240AD 6450 Wedgwood Rd, Suite 130 Maple Grove MN 55311 +1 763 398 1056 '... a look of horror, akin to that on children's faces at Shrek movies when they realize their parents know all the words to "I'm a Believer."'