This is the best WYSIWYG editor out there, and it's unfortunate that the author has gone MIA. Here is the fix to get this working for your site, and if the author does not respond, I'll release another version so we can easily add it to our sites.
In the file: /wp-content/wysiwyg-widgets/php/backend.php
Remove Line 74:
wp_tiny_mce(true,array('height' => 350));
The height will now extend a little past the dialog box, but well worth having a working plugin!