Installed this (and another plugin that had the same issue, I'm notifying both) on my site (I run a network) for my users to use on their sites within the network. I have logged in under a user's account, and though I am able to activate it, the widget never shows up for use on the Appearance -> Widgets screen.
I tried one click installs, installing manually via FTP (the folder as well as just the .php file from the folder), as well as network activating. Nothing seems to make a difference.
I really need one of these two plugins to work! Please help if you are the plugin author, or have dealt with this issue before!