customizing newsticker variables: problem displaying widget

[Joost Kremers <joostkremers@yahoo.com>]

hi all,

i'm trying to set up newsticker, but i'm running into a strange problem
customizing some variables. when i do

M-x customize-variable RET newstnewsticker-treeview-treewindow-width RET

or 

M-x customize-variable RET newstnewsticker-treeview-listwindow-height RET

the customization buffer shows the buttons "Set for current session", "Save for
future settings", etc, but the variable itself is not shown. an error is
displayed in the minibuffer, here copied from the *Messages* buffer:

widget-apply: Symbol's function definition is void: nil

if i go through M-x customize-group RET newsticker RET, and then select
"Newsticker Reader" and then "Newsticker Treeview", the states of these
variables are "HIDDEN", but if i click "Show", the entire item disappears and
the same error is displayed.

this is GNU Emacs 23.1.1, GTK+, with newsticker preinstalled. there's nothing
weird in the defcustom definitions of both variables. the error also occurs when
emacs is started with -Q.

anyone have an idea what's wrong here? i manually added both variables to
~/.emacs.d/custom.el (which is where i keep my customisations) and they work
fine.

TIA


-- 
Joost Kremers                                      joostkremers@yahoo.com
Selbst in die Unterwelt dringt durch Spalten Licht
EN:SiS(9)