featured image showing in post… error reported

[Topic line decapped – please do not “yell” here]

I get this in the back end, after updating…

Warning: trim() expects parameter 1 to be string, array given in /home/content/82/10373482/html/wp-content/plugins/easy-nivo-slider/3rd-party/filosofo-custom-image-sizes.php on line 31

how do i get rid of the dang featured image inside the single post…???