[validate] error with .rules("add") in Opera 9.51

[codinghorror]

We only get this error on Opera; works OK on IE7 / FF3 / Safari31 (windows versions)

message: Statement on line 104: Cannot convert undefined or null to Object

Backtrace:

Line 104 of linked script http://localhost/content/js/jquery.validate.js

var staticRules = jQuery.data(element.form, 'validator').settings.rules;

Line 51 of inline#2 script in http://localhost/test: In function initValidation

$("#post-text").rules("add", { required: true, minlength: 5 });

Line 58 of inline#2 script in http://localhost/test

initValidation();

[codinghorror]

we are using a textarea control -- not an input type="text"

[joern]

Can you provide a simple testpage?