I am having the exact same issue. I just downloaded a trial version of Snap! and when I try to use any of the functions under the Snap! ribbon, I get the following message: "This presentation does not have active content enabled. It must be set to enabled in order to work with Snap!. Please check the PowerPoint options to enable this content."
I have tried the location recommendation above, along with allowing all content through the Trust Center settings.
I am using Office 2010 and Windows 7.
