If you are not able to complete the W9 form, you will need to ensure that you have the latest version of Adobe Reader installed. You can get the latest version by going to www.adobe.com/downloads Once you have the latest version installed, your form will pop up in the window there.
If that doesn't work, you may also want to attempt filling it out using a different browser, in particular if you are using Google Chrome. This will ensure that there is nothing in the cache when you fill it out.
You can find the form by going directly to https://www.jvzoo.com/base/W9