in moodle19/admin/user/user_bulk.php
(and in lot more pages) I often get firebug errors.

In page
moodle19/admin/user/user_bulk.php of today's daily release
the error is in the function lockoptionsallsetup(formid)
and it is:
form has no properties
lockoptionsallsetup("mform1")javascript-static... (line 161)
for (var i = 0; i < form.elements.length; i++){