[jQuery] Newbie question (Bassistance Validate) - error msg does not go away

[mango]

i am new to jquery and started using the validate plugin with jquery.
I tried the demo but have problems using my own jsp form.

i have added the usual
$(document).ready(function() {
        $('#customForm').validate({
        rules: {
        field1: "required",
        ...}
        messages: { ...}
         });


the error messages showing up fine, but once i start typing into the
field, the error msg does not go away. where should i start to look?
can someone provide any pointers?

thanks