Need help activating Pop Up! plugin


I'm trying to install and configure the Pop Up! Plugin and am getting this error message:
I get this error anytime I click on anything in the Sidebar for this plug-in. I can see it's installed and it says it's active/successful, but when I go to click on the links/settings/etc. This message appears....

Fatal error: Call to undefined method stdClass::add_help_tab() in /home/collinno/public_html/wp-content/plugins/popover/popoverincludes/classes/ on line 53

Any ideas on how to fix this?

Please help - thank you!


The website is: