[jQuery] [validate] error when I validate file

[jQuery] [validate] error when I validate file


OK,
I have simple form that I require file upload.
when i focus on the filed and press enter I get this error
[Exception... "'Permission denied to get property
HTMLInputElement.nodeType' when calling method:
[nsIDOMEventListener::handleEvent]" nsresult: "0x8057001e
(NS_ERROR_XPC_JS_THREW_STRING)" location: "<unknown>" data: no]
in firebug. and the form submits ignoring the validation.
my code
$("#order_form").validate({
     errorClass: "invalid",
     rules: {
         upload_file:{required:true},
    }, debug:true
    });
I tried using the latest validation version and svn version
any ideas