I found a couple of bugs in wp-contact-form-7.php.
1) in function wpcf7_plugin_url( $path = ” )
global $wp_version;
Needs to be added before the first if statement so that the variable is available within that function.
2) in function wpcf7_enqueue_scripts()
TRUE should be removed as a parameter passed to wp_enqueue_script as it’s not a valid parameter.