error message: missing argument in admin-functions

Hi,
I get a php warning for setting up categories. Does anybody understand what’s missing here?
I did create a drop-down menu for categories in index.php. Do I need to adjust something in wp-admin/admin-functions.php?
PHP Warning: Missing argument 1 for wp_dropdown_cats() in /mnt_filer/lserv/v/i/www.visioform.com/wpde/wp-admin/admin-functions.php on line 93
Line 93 is:
function wp_dropdown_cats($currentcat, $currentparent = 0, $parent = 0, $level = 0, $categories = 0)
Thanks
ulla at visioform