PolyLang Error In WordPress 3.81

I was getting an error in one of my plug-ins after the automatic WP 3.81 upgrade. So I disabled all my plug-ins. I tried to activate the PolyLang plugin with all the other plug-ins disabled and got the following error:

Fatal error: Call to a member function get_post() on a non-object in /home2/francis6/public_html/blackberry-trackball.com/wp-content/plugins/polylang/include/api.php on line 71

Please help.

Thanks,

John

https://www.ads-software.com/plugins/polylang/