Sidekick uses Word to edit and view the letters, you must have Word installed on your computer. Sidekick needs to run as administrator in order for your computer to allow Sidekick to open Word for you.
How to give Sidekick permission:
Before opening Sidekick from your desktop, right click on the Sidekick icon, choose Properties, select the tab labeled Compatibility, check the box next to run as administrator. Apply and Save/OK