I just downloaded and installed this plugin to use on my website for potential clients to download a digital portfolio of my formatting skills (I'm an author/publisher just starting to take on outside clients). So far the plugin is very easy to use! But, I wanted to try uploading my e-book files, because I've setup PayPal to allow me to do so. And WP doesn't allow uploads of certain file types for security purposes. So, I sent an email message to the contact us, and within 5 minutes, I had a response! And, the tip I was given actually worked, so I'm a happy camper! This is one satisfied customer!