When I installed FOOTER CONTENT plug-in, I was locked out of my site... why?

Sorry for picking the wrong category, but I had to uninstall "Footer Content". See I installed the Footer Content plugin and was instantly locked out of the front and back end of my website (error message said plugin only available for multisite). I went via FTP into the code and deleted the plugin, and was able to get back in. So while I have no IMMEDIATE concern, I'd like to know if there is some type of warning included with plugins that say DO NOT INSTALL unless you are using with a multisite. Perhaps this plug-in just doesn't jive with my wordpress theme. Not sure but please help with any information you might have.