[jQuery] Validation jQuery plugin - onfocusout throws error

[henry]

jquery: 1.2.3
jquery validation plugin: 1.2.1

I have:
<form id="myform" name="myform">
...
</form>

$().ready(){
$("#myform").validate({onfocusout:true});
}


<<<< firebug error message >>>

validator.settings["on" + event.type].call is not a function

on jquery.validate.js line 250


same error msg is thrown with onkeyup as well... Why??

Thank you.