It's important that:
-You do not have any other version of the software from any other source (stardock.com for example)
If you do, you need to uninstall that other version
-That you are logged into Steam and not as a 'guest'
-In the install directory, run sassteam.exe and see if you are able to use the product again.
\Program Files (x86)\Stardock\Fences
-If the above fails, uninstall / reinstall from within Steam (and only from within Steam) and try again.