It should work because the demo site uses it and I just did a test with my local site version. I know this sounds strange but you do have it active and checked the box on the page in the editor to hide the title?
Something else must be conflicting with it then if the plugin is not working. The live demo site is on WP 3.9 and the page title is hidden on the pages the box is checked. One way to find out is to disable your other plugins one by one and test the page to see if the title gets hidden.
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