possible bug in customize-save?

[Michelangelo Rodriguez]

m-x customize-saved
When i type C-x C-s for saving, with debug-on-error on, i get the
following backtrace:
Debugger entered--Lisp error: (void-function nil)
  nil(nil)
  widget-apply(nil :value-get)
  widget-value(nil)
  custom-variable-modified-p((custom-variable :tag "Package Archives" :value 
package-archives :custom-form edit :custom-magic (custom-magic :args (nil) 
:parent #1 :indent 0 :children nil :from #<marker (moves after insertion) at 
2989 in *Customize Saved*> :to #<marker at 2989 in *Customize Saved*> :buttons 
nil :value nil) :buttons ((documentation-string :args nil :value "An alist of 
archives from which to fetch.\nThe defa..." :indent 3 :visibility-widget 
custom-visibility :parent #1 :doc-overlay #<overlay from 2989 to 3034 in 
*Customize Saved*> :buttons ((custom-visibility :args nil :value nil :help-echo 
"Show or hide rest of the documentation." :on "Hide" :off "More" :always-active 
t :action widget-parent-action :parent #13 :indent 3 :button-overlay #<overlay 
from 3034 to 3038 in *Customize Saved*> :from #<marker (moves after insertion) 
at 3034 in *Customize Saved*> :to #<marker at 3038 in *Customize Saved*>)) 
:from #<marker (moves after insertion) at 2989 in *Customize Saved*> :to 
#<marker at 3039 in *Customize Saved*>) (custom-magic :args (nil) :parent #1 
:indent 0 :children nil :from #<marker (moves after insertion) at 2989 in 
*Customize Saved*> :to #<marker at 2989 in *Customize Saved*> :buttons nil 
:value nil) (item :format "%{%t%} " :sample-face custom-variable-tag :tag 
"Package Archives" :parent #1 :indent 0 :sample-overlay #<overlay from 2971 to 
2987 in *Customize Saved*> :from #<marker (moves after insertion) at 2971 in 
*Customize Saved*> :to #<marker at 2988 in *Customize Saved*>) 
(custom-visibility :args nil :value nil :help-echo "Show the value of this 
option." :on-glyph "down" :on "Hide" :off-glyph "right" :off "Show Value" 
:action custom-toggle-hide-variable :parent #1 :indent 0 :suppress-face t 
:button-overlay #<overlay from 2960 to 2970 in *Customize Saved*> :from 
#<marker (moves after insertion) at 2960 in *Customize Saved*> :to #<marker at 
2970 in *Customize Saved*>)) :documentation-indent 3 :children nil 
:custom-state hidden :from #<marker (moves after insertion) at 2960 in 
*Customize Saved*> :to #<marker at 3039 in *Customize Saved*>))
  custom-variable-state-set((custom-variable :tag "Package Archives" :value 
package-archives :custom-form edit :custom-magic (custom-magic :args (nil) 
:parent #1 :indent 0 :children nil :from #<marker (moves after insertion) at 
2989 in *Customize Saved*> :to #<marker at 2989 in *Customize Saved*> :buttons 
nil :value nil) :buttons ((documentation-string :args nil :value "An alist of 
archives from which to fetch.\nThe defa..." :indent 3 :visibility-widget 
custom-visibility :parent #1 :doc-overlay #<overlay from 2989 to 3034 in 
*Customize Saved*> :buttons ((custom-visibility :args nil :value nil :help-echo 
"Show or hide rest of the documentation." :on "Hide" :off "More" :always-active 
t :action widget-parent-action :parent #13 :indent 3 :button-overlay #<overlay 
from 3034 to 3038 in *Customize Saved*> :from #<marker (moves after insertion) 
at 3034 in *Customize Saved*> :to #<marker at 3038 in *Customize Saved*>)) 
:from #<marker (moves after insertion) at 2989 in *Customize Saved*> :to 
#<marker at 3039 in *Customize Saved*>) (custom-magic :args (nil) :parent #1 
:indent 0 :children nil :from #<marker (moves after insertion) at 2989 in 
*Customize Saved*> :to #<marker at 2989 in *Customize Saved*> :buttons nil 
:value nil) (item :format "%{%t%} " :sample-face custom-variable-tag :tag 
"Package Archives" :parent #1 :indent 0 :sample-overlay #<overlay from 2971 to 
2987 in *Customize Saved*> :from #<marker (moves after insertion) at 2971 in 
*Customize Saved*> :to #<marker at 2988 in *Customize Saved*>) 
(custom-visibility :args nil :value nil :help-echo "Show the value of this 
option." :on-glyph "down" :on "Hide" :off-glyph "right" :off "Show Value" 
:action custom-toggle-hide-variable :parent #1 :indent 0 :suppress-face t 
:button-overlay #<overlay from 2960 to 2970 in *Customize Saved*> :from 
#<marker (moves after insertion) at 2960 in *Customize Saved*> :to #<marker at 
2970 in *Customize Saved*>)) :documentation-indent 3 :children nil 
:custom-state hidden :from #<marker (moves after insertion) at 2960 in 
*Customize Saved*> :to #<marker at 3039 in *Customize Saved*>))
  custom-variable-state-set-and-redraw((custom-variable :tag "Package Archives" 
:value package-archives :custom-form edit :custom-magic (custom-magic :args 
(nil) :parent #1 :indent 0 :children nil :from #<marker (moves after insertion) 
at 2989 in *Customize Saved*> :to #<marker at 2989 in *Customize Saved*> 
:buttons nil :value nil) :buttons ((documentation-string :args nil :value "An 
alist of archives from which to fetch.\nThe defa..." :indent 3 
:visibility-widget custom-visibility :parent #1 :doc-overlay #<overlay from 
2989 to 3034 in *Customize Saved*> :buttons ((custom-visibility :args nil 
:value nil :help-echo "Show or hide rest of the documentation." :on "Hide" :off 
"More" :always-active t :action widget-parent-action :parent #13 :indent 3 
:button-overlay #<overlay from 3034 to 3038 in *Customize Saved*> :from 
#<marker (moves after insertion) at 3034 in *Customize Saved*> :to #<marker at 
3038 in *Customize Saved*>)) :from #<marker (moves after insertion) at 2989 in 
*Customize Saved*> :to #<marker at 3039 in *Customize Saved*>) (custom-magic 
:args (nil) :parent #1 :indent 0 :children nil :from #<marker (moves after 
insertion) at 2989 in *Customize Saved*> :to #<marker at 2989 in *Customize 
Saved*> :buttons nil :value nil) (item :format "%{%t%} " :sample-face 
custom-variable-tag :tag "Package Archives" :parent #1 :indent 0 
:sample-overlay #<overlay from 2971 to 2987 in *Customize Saved*> :from 
#<marker (moves after insertion) at 2971 in *Customize Saved*> :to #<marker at 
2988 in *Customize Saved*>) (custom-visibility :args nil :value nil :help-echo 
"Show the value of this option." :on-glyph "down" :on "Hide" :off-glyph "right" 
:off "Show Value" :action custom-toggle-hide-variable :parent #1 :indent 0 
:suppress-face t :button-overlay #<overlay from 2960 to 2970 in *Customize 
Saved*> :from #<marker (moves after insertion) at 2960 in *Customize Saved*> 
:to #<marker at 2970 in *Customize Saved*>)) :documentation-indent 3 :children 
nil :custom-state hidden :from #<marker (moves after insertion) at 2960 in 
*Customize Saved*> :to #<marker at 3039 in *Customize Saved*>))
  widget-apply((custom-variable :tag "Package Archives" :value package-archives 
:custom-form edit :custom-magic (custom-magic :args (nil) :parent #1 :indent 0 
:children nil :from #<marker (moves after insertion) at 2989 in *Customize 
Saved*> :to #<marker at 2989 in *Customize Saved*> :buttons nil :value nil) 
:buttons ((documentation-string :args nil :value "An alist of archives from 
which to fetch.\nThe defa..." :indent 3 :visibility-widget custom-visibility 
:parent #1 :doc-overlay #<overlay from 2989 to 3034 in *Customize Saved*> 
:buttons ((custom-visibility :args nil :value nil :help-echo "Show or hide rest 
of the documentation." :on "Hide" :off "More" :always-active t :action 
widget-parent-action :parent #13 :indent 3 :button-overlay #<overlay from 3034 
to 3038 in *Customize Saved*> :from #<marker (moves after insertion) at 3034 in 
*Customize Saved*> :to #<marker at 3038 in *Customize Saved*>)) :from #<marker 
(moves after insertion) at 2989 in *Customize Saved*> :to #<marker at 3039 in 
*Customize Saved*>) (custom-magic :args (nil) :parent #1 :indent 0 :children 
nil :from #<marker (moves after insertion) at 2989 in *Customize Saved*> :to 
#<marker at 2989 in *Customize Saved*> :buttons nil :value nil) (item :format 
"%{%t%} " :sample-face custom-variable-tag :tag "Package Archives" :parent #1 
:indent 0 :sample-overlay #<overlay from 2971 to 2987 in *Customize Saved*> 
:from #<marker (moves after insertion) at 2971 in *Customize Saved*> :to 
#<marker at 2988 in *Customize Saved*>) (custom-visibility :args nil :value nil 
:help-echo "Show the value of this option." :on-glyph "down" :on "Hide" 
:off-glyph "right" :off "Show Value" :action custom-toggle-hide-variable 
:parent #1 :indent 0 :suppress-face t :button-overlay #<overlay from 2960 to 
2970 in *Customize Saved*> :from #<marker (moves after insertion) at 2960 in 
*Customize Saved*> :to #<marker at 2970 in *Customize Saved*>)) 
:documentation-indent 3 :children nil :custom-state hidden :from #<marker 
(moves after insertion) at 2960 in *Customize Saved*> :to #<marker at 3039 in 
*Customize Saved*>) :custom-state-set-and-redraw)
  #f(compiled-function (&rest ignore) "Set all edited settings, then save all 
settings that have been set.\nIf a setting was edited and set before, this 
saves it.  If a\nsetting was merely edited before, this sets it then saves it." 
(interactive nil) #<bytecode 0xae594f97d9b5d8a>)()
  apply(#f(compiled-function (&rest ignore) "Set all edited settings, then save 
all settings that have been set.\nIf a setting was edited and set before, this 
saves it.  If a\nsetting was merely edited before, this sets it then saves it." 
(interactive nil) #<bytecode 0xae594f97d9b5d8a>) nil)
  ad-Advice-Custom-save(#f(compiled-function (&rest ignore) "Set all edited 
settings, then save all settings that have been set.\nIf a setting was edited 
and set before, this saves it.  If a\nsetting was merely edited before, this 
sets it then saves it." (interactive nil) #<bytecode 0xae594f97d9b5d8a>))
  apply(ad-Advice-Custom-save #f(compiled-function (&rest ignore) "Set all 
edited settings, then save all settings that have been set.\nIf a setting was 
edited and set before, this saves it.  If a\nsetting was merely edited before, 
this sets it then saves it." (interactive nil) #<bytecode 0xae594f97d9b5d8a>) 
nil)
  Custom-save()
  #<subr funcall-interactively>(Custom-save)
  apply(#<subr funcall-interactively> Custom-save nil)
  ad-Advice-funcall-interactively(#<subr funcall-interactively> Custom-save)
  apply(ad-Advice-funcall-interactively #<subr funcall-interactively> 
Custom-save)
  funcall-interactively(Custom-save)
  #<subr call-interactively>(Custom-save nil nil)
  ad-Advice-call-interactively(#<subr call-interactively> Custom-save nil nil)
  apply(ad-Advice-call-interactively #<subr call-interactively> (Custom-save 
nil nil))
  call-interactively(Custom-save nil nil)
  command-execute(Custom-save)

In my init file ~/.emacs.d/init.el it seems to be normal, the variable
package-archive inside customize appears as each other.
what could be the problem?
how can i investigate furthermore on it?
Regards,
Michelangelo