[Plugin: Contact Form 7] Adding File Upload to working form produces JS error

I have the same problem, the error shows up when I have jQuery 1.5 included on my site. Works with jQuery 1.4.4

same here using the latest versions of the form and WP.

the mail and attachment are sent just fine but the animation continuous … trying to debug it with firebug … uncommenting the handleerror en setting the ok to true; it takes me to the scripts.js and gives me the error that the data var is undefined but still sent the mail just fine … removing the file input field and the callback works.

*bump*

I too have the same problem.
Does anyone maybe have a workaround?

Cheers,
Constantin

This is still an issue. Temporary fix is to force and old version of jquery in fucntions.php

function my_scripts_method() {
    wp_deregister_script( 'jquery' );
    wp_register_script( 'jquery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js');
    wp_enqueue_script( 'jquery' );
}
add_action('wp_enqueue_scripts', 'my_scripts_method');